Nothing illustrates the importance of context more than a word that can have opposite meanings.

All Over: available everywhere / no longer available
Anxious: eager expectation / fearful apprehension
Apart: separated / included (a part)
Apology: statement of contrition / statement of defense
Argue: assert / deny
Awful: awe-inspiring / terribly bad
Bad: terrible / wonderfully good
Bill: money held ($5 bill) / money owed
Bolt: hold securely / run away
Bound: moving / unable to move
Buckle: hold together / collapse or fall apart
Carry On: behave normally / behave abnormally
Cleave: cut apart / join together
Clip: fasten / detach
Consult: give advice / ask for advice
Citation: award for good behavior / penalty for bad behavior
Clip: attach to / cut off from
Custom: common practice / special treatment
Cut: get into (a line) / get out of (a class)
Downhill: a better direction / a worse direction
Dress: add a covering (clothes)/ remove a covering (plucked feathers)
Dust: remove fine particles / cover with fine particles

Enjoin: prescribe / prohibit
Execute: kill / implement, bringing it to life
Fast: moving rapidly / holding a fixed position
Fight With: join in battle / oppose in battleFinished: completed / destroyed
First Degree: most severe (murder) / least severe (burns)
Fix: predicament / solution
Garnish: enhance (food) / take away (wages)
Go Off: begin operation / cease operation
Grade: incline / level
Hold up: support / impede
Impregnable: not enterable / enterable
Lease: buy use of / sell use of
Left: remaining / gone away
Legendary: famously true / famously imaginary
Mirror Image: exactly the same / exactly the opposite
Moot: arguable / not worthy of an argument
Oblige: require a favor / do a favor
Out: visible (stars) / invisible (lights)
Oversight: watchful control / something not noticed
Peer: unequal (nobility to a peasant) / an equal
Pitted: with pits / with pits removed

Put out: extinguish / initiate
Reaching: achieved (reaching the goal) / not achieved (reaching for the goal)
Rent: buy use of / sell use of
Resign: quit / continue
Sanction: approve / forbid (boycot)
Scan: carefully inspect / skim over
Screen: make visible (as a movie) / hide from view
Seeded: with seeds / with seeds removed
Shelled: having a shell / having no shell
Skinned: with the skin on / with the skin removed
Splice: join / separate
Strike: hit (oil) / fail to hit (baseball)
Submit: offer / accept
Table: bring up for discussion / withdraw from discussion
Temper: soften / strengthen
Throw out: disregard / consider
Transparent: invisible / obvious
Trim: add (decorations) / remove (excess)
Variety: particular type / many types
Wear: endure / deteriorate
Weather: withstand the elements / worn away by the elements
Wind Up: end / start up