Contronyms

Contronyms, also known as antagonyms, autoantonyms or Janus words, are words which, by some freak of language evolution, have two opposite meanings, according to the context in which they occur. For example, with can mean 'alongside' in 'Come with me' but 'against' or 'in opposition to' in 'Hannibal fought with the Romans'. A door that is bolted is secure, but a horse that has bolted has taken off. If you wind up a meeting you finish it; if you wind up a watch you start it. Is it any wonder that English is so difficult to learn?

~ A ~
Aboard	Alongside ~~~ Inside
Adumbrate	To clarify ~~~ To cast a shadow over
Against	In the direction of and in contact with ~~~ In an opposite direction
Alight	Settle onto ~~~ Dismount from
Anabasis	A military advance ~~~ A military retreat
Anon	Immediately (archaic) or soon ~~~ Later
Anxious	Full of mental distress because of apprehension of danger or misfortune ~~~ Eager or looking forward to something
Apparent	Not clear or certain (For now, he is the apparent winner of the contest) ~~~ Obvious (The solution to the problem was apparent to all)
Argue	To try to prove by argument ~~~ To argue against
Assume	To actually have (To assume office) ~~~ To hope to have (He assumed he would be elected)
Aught	All ~~~ Nothing
Avocation	A hobby ~~~ A regular occupation
Awful	Extremely unpleasant, ugly ~~~ Awe-inspiring (a feeling of admiration)
~ B ~
Biannual	Twice a year ~~~ Once every two years
Bimonthly	Twice a month ~~~ Once every two months
Biweekly	Twice a week ~~~ Once every two weeks
Bolt	Secure ~~~ Run away
Bound	Moving (He was bound for London) ~~~ Unable to move (He was bound to a post)
Buckle	To hold together (Buckle your belt) ~~~ To fall apart (Buckle under pressure)
By	Multiplication (Three by five inches square) ~~~ Division (Divide six by two)
~ C ~
Certain	Definite ~~~ Hard to specify (He had a certain feeling)
Charter	Grant for pay ~~~ Use for pay
Cipher	Zero ~~~ Any number
Citation	Given for doing good (An official commendation) ~~~ Given for doing bad (A court summons)
Cleave	To adhere tightly ~~~ To cut apart
Clip	To attach ~~~ To cut off
Cognomen	First name ~~~ Last name
Comprise	To contain entirely (The United States comprises 50 states) ~~~ To be included in (The 50 states comprise the United States)
Cork	To take out ~~~ To insert (a cork into/from a bottle)
Consult	Ask for advice ~~~ Give advice
Contingent	Unpredictable ~~~ Dependent on a known condition
Counterfeit	A legitimate copy (archaic) ~~~ A copy meant to deceive
Critical	Opposed to ("critical of") ~~~ essential to ("critical to")
Crop	To plant or grow ~~~ To cut or harvest
Cull	To select ~~~ To reject
Custom	Usual ~~~ Special (Custom-built)
~ D ~
Deceptively	More than it looks ~~~ Less than it looks
Discursive	Proceeding coherently from topic to topic ~~~ Moving aimlessly from topic to topic
Down	Hill ~~~ Valley
Dress	Put covering on (usually clothes) ~~~ Take covering (usually skin) off
Dust	To remove dust (As in cleaning furniture) ~~~ To apply dust (As in fingerprinting)
Dyke	Wall ~~~ ditch
~ E ~
Effectively	In effect (Doing the equivalent of the action but not the real thing) ~~~ With effect (Doing the action and doing it well) [Contrast 'He is effectively lying' with 'He is lying effectively']
Enjoin	To order to do something ~~~ To stop someone from doing something (such as in law by an injunction)
~ F ~
Fast	Moving rapidly ~~~ Unable to move (He was held fast to the spot)
Fearful	Causing fear ~~~ Being afraid
Filter	To allow to pass through ~~~ To prevent from passing through
Finish	Kill ~~~ Perfect (eg. at a finishing school)
Fireman	Firefighter ~~~ Fire-stoker (on a train, ship)
Fix	To restore to function (Fixing the television) ~~~ To make non-functional (Fixing the dog, i.e castrate)
Flesh	To add substance (flesh out) ~~~ take away (clean a hide of flesh)
Flog	Critise harshly ~~~ Promote aggressively
~ G ~
Garnish	Enhance (e.g. food) ~~~ Curtail (e.g. wages)
Grade	Incline ~~~ Level
~ H ~
Handicap	Advantage (in golf) ~~~ Disadvantage
Help	Assist ~~~ Prevent ("It couldn't be helped.")
Homely	Ugly (US) ~~~ Pleasant (UK)
Hysterical	Being overwhelmed with fear ~~~ Very funny
~ I ~
Impregnable	Not pregnable ~~~ Capable of being impregnated
Incorporate	When a town is incorporated, it is formed ~~~ when it is incorporated into a city, the town is destroyed
Inflammable	Burns easily ~~~ Does not burn (Only the first definition is correct; many wrongly assume that the prefix in- gives it the second meaning)
Inoculate	To protect against ~~~ To infect with
~ J ~
Joint	To combine ~~~ To separate (to joint meat)
~ L ~
Last	Just prior ~~~ Final (His last book will be his last publication)
Lease	To loan out for money ~~~ To 'borrow' for money
Left	To remain ~~~ To have gone ("Of all my visitors, only Henry's left." could mean Henry's the only one still remaining or that he's the only one to have gone)
Let	To hinder (archaic) ~~~ To allow
License	Freedom or permission to do something ~~~ Undue or excessive freedom or liberty
Literally	Actually; really ~~~ Figuratively; virtually
Livid	Pale, ashen ~~~ Dark-grey-blue
~ M ~
Mad	Carried away by enthusiasm or desire ~~~ Carried away by hatred or anger
Mark	Write ~~~ Read ("mark my words")
Model	Archetype ~~~ Copy
Moot	Debatable; arguable ~~~ Academic; irrelevant
Mortar	Glue together ~~~ Blow apart
~ N ~
Nervy	Showing calm courage ~~~ Exitable
~ O ~
Out	Visible (The stars are out) ~~~ Invisible (The lights are out)
Overlook	To pay attention to, inspect ~~~ To ignore
Oversight	Watchful and responsible care ~~~ An omission or error due to carelessness
~ P ~
Peer	Noble ~~~ Person of equal rank
Persuse	Read in a casual way, skim ~~~ To read with great attention to detail, study carefully
Pitch	Erect and fix firmly in place ~~~ Throw away
Policy	Required activity without exception ~~~ An optional course of action
Practiced	Experienced, expert ~~~ Inexperienced effort
Presently	Now ~~~ After some time
Priceless	Have a very high value ~~~ Having no marked value
Protest	To object ~~~ To affirm
Put	Lay ~~~ Throw
Puzzle	To pose a problem ~~~ To solve a problem
~ Q ~
Qualified	Competent ~~~ Limited ("The party was a qualified success")
Quantum	Very small (e.g. in Physics) ~~~ Very large (e.g. "Quantum leap")
Quiddity	Essence ~~~ Trifling point
Quite	Completely ~~~ Not completely (Quite empty means totally empty, while quite full means not completely full)
~ R ~
Ravel	To disentangle ~~~ To tangle, entangle
Recover	Hide away (cover again) ~~~ Bring out (recover from hidden place)
Reel	Wind onto ~~~ Let out from
Refrain	Repeat (the chorus of a song) ~~~ Stop (refrain from swearing)
Release	Let go ~~~ Hold on to (lease the property again)[re-lease]
Rent	Buy use of ~~~ Sell use of
Replace	Take away (replace the stained clothing) ~~~ Put back (replace the clothes in the drawer)
Repress	Hold back ~~~ Put forth (press again) [re-press]
Reprove	Rebuke ~~~ Support (re-prove someone's innocence)
Reservation	What you make when you know where you want to go ~~~ What you have if you are not sure you want to go
Resign	To quit a contract ~~~ To sign a contract again (re-sign)
Rocky	Firm, steadfast ~~~ Tending to sway (a rocky stepladder)
Root	To establish (The seed took root) ~~~ To remove (Root out the weeds)
~ S ~
Sanction	Support for an action ~~~ Penalty for an action (The MP was sanctioned for inappropriate behaviour
Sanguine	Murderous ~~~ Cheerfully optimistic
Scan	To examine closely ~~~ To look over hastily
Screen	Show ~~~ Hide
Secrete	To extrude ~~~ To hide
Secreted	Put out, released ~~~ Placed out of sight
Seed	To spread seeds ~~~ To remove seeds (from a fruit, say)
Seeded	With seeds ~~~ Without seeds
Settle	To move (the dust settled) ~~~ To stop moving (he settled into his seat)
Siren	Seductive sound ~~~ Harsh sound
Skin	To cover with skin ~~~ to remove outer covering or skin
Snap	Break into pieces ( The glass snapped into pieces) ~~~ Fasten together (The pieces snapped together)
Splice	To join together ~~~ To cut in two
Stain	To colour ~~~ To discolour
Stipulate	Request explicitly ~~~ Agree to
~ T ~
Table	Propose (In UK) ~~~ Set aside (In USA)
Temper	Calmness ~~~ Passion / Harden (steel) ~~~ Soften (justice)
Terrific	Extraordinarily good (informal) ~~~ Causing terror
Tilt	To incline toward ~~~ To charge against
Transparent	Easily seen (His motives were transparent) ~~~ Invisible
Trim	To add things to (trim a Christmas tree) ~~~ Take pieces off (trim hair)
Trip	To stumble ~~~ To move gracefully (Trip the light fantastic)
~ U ~
Unbending	Rigid ~~~ Relaxing
Unqualified	Not qualified ~~~ Very qualified ("The dance was an unqualified success")
~ V ~
Vegetative	Full of life ~~~ Dull, apathetic, passive
Vernacular	Nonstandard speech ~~~ Standard speech
Vital	Lively ~~~ Deadly
~ W ~
Water	Pour water out ~~~ Take on water
Wear	Endure through use ~~~ Decay through use
Weather	Withstand ~~~ Erode away
Widdershins	Counterclockwise ~~~ (In the southern hemisphere) Clockwise
With	Alongside ~~~ Against
Wraith	Ghost of a dead person ~~~ Apparition of a living person
~ X ~
X	Select (mark with an X) ~~~ Deselect (cross out)