Words that have meanings that contradict each other.

AnabasisA military advance A military retreat
AnxiousFull of mental distress because of apprehension of danger or misfortune [in effect, seeking to avoid] (We were anxious about the nearby gunshots.) Eager or looking forward to (Until you returned, I was anxious to see you.)
ApparentNot clear or certain (For now, he is the apparent winner of the contest.) Obvious (The solution to the problem was apparent to all.)
Avocationa hobby a regular occupation [and one could say it's a triple autoantonym if you agree that the archaic meaning of "a distraction" is the opposite of working (even at a hobby) and if you agree that the obsolete meaning of "a calling away" takes you away from (the opposite of participating in) your hobbies, work, and even your distractions!]
AwfulExtremely unpleasant, ugly Awe-inspiring [typically, a feeling of admiration]
Cite, CitationFor doing good (such as military gallantry) for doing bad (such as from a traffic policeman)
CleaveTo adhere tightly To cut apart
DustTo remove dust To apply dust (as in fingerprinting)
EnjoinTo order someone to do something To stop someone from doing something [such as in law by an injunction]
FearfulCausing fear Being afraid
HystericalBeing overwhelmed with fear [in some cases] Being funny
Inflammable [a pseudo-autoantonym!]Burns easily [the incorrect assumption by many that the prefix in- makes it mean:] Does not burn [Only the first definition is correct; the risk of confusion has removed this word from gasoline trucks!]
Lease, Let, Rent[in essence] To loan out for money To "borrow" for money
Let[Archaic] To hinder To allow
LicenseLiberty or permission to do something Undue or excessive freedom or liberty
Moot[a slight stretch here] A moot point is one that is debatable, yet is also of no significance or has been previously decided, so why debate it?
OversightWatchful and responsible care An omission or error due to carelessness
PracticedExperienced, expert (I am practiced in my work) Inexperienced effort (The child practiced coloring)
PrescribeTo lay down a rule To become unenforceable
RiotViolent disorder Revelry
SanctionSupport for an action (They sanctioned our efforts.)A penalty for an action (The Congressman was sanctioned for inappropriate behavior.)
Sanguine(Now poetic) Causing or delighting in bloodshed [according to contributor, also describes a person worked up into a bloody rage] A person hopeful or confident of success [essentially someone calm about something]
SecretedHaving put out, releasedPlaced out of sight
Shank(Informal) The early part of a period of time (It was just the shank of the evening when the party began.) (Informal) The latter part of a period of time (It was the shank of the evening when the party ended.)
Skinto cover with a skin to remove outer covering or skin
Strike outAn ending, as in "The batter struck out." A beginning, as in "I thought it was time to strike out on my own."
Terrific (Informal) Extraordinarily good Causing terror