Words containing within themselves antithetical meanings
Examples:
- “Apparent” can mean “obvious” or “seeming, but in fact not”.
- “Awful” can mean “worthy of awe” or “very bad”.
- “Back” can mean “regressive” as in “to go back in time”, or it can mean “progressive” as in “to push back a deadline”.
- “Citation” can mean “commendation” or a “summons to appear in court”.
- “To cleave” can mean “to cling” or “to split”.
- “To comprise” can mean “to consist of” or “to make up or constitute”.
- “To dust” can mean to remove dust (cleaning a house) or to add dust (dust a cake with powered sugar).
- “Fast” can mean “moving quickly” as in “running fast,” or it can mean “not moving” as in “stuck fast.”
- “To fight with someone” can mean “to fight against someone” or “to fight alongside someone”.
- “Impregnable” can mean “able to be impregnated” or “incapable of being entered”.
- “Moot” can mean worthy of discussion or not worthy of discussion.
- “To overlook” can mean “to inspect” or “to fail to notice”.
- “Oversight” (uncountable) means “supervision”, “an oversight” (countable) means “not noticing something”.
- “Off” can mean “deactivated” as in “to turn off”, or it can mean “activated” as in “the alarm went off”.
- “Redundant” can mean “useless” or “extra caution”.
- “Refrain” means both non-action and the repetition of an action, e.g. in musical notation.
- “Resign” can mean “give up or quit” or “continue”.
- “To sanction” means “to permit”, and also “to punish”.
- “Shelled” can mean “having a shell” or “has had the shell removed” (as in shelling).
- “To skin” means “to cover with skin” (as in to skin a drum) as well as “to strip or peel off” (as in to skin an animal).
- “To stint” means “to stop”, but the noun “stint” refers to the interval of work between stops.
- “Strike”, in baseball terms, can mean “to hit the ball” or “to miss the ball”.
- “To weather” can mean “to endure” (as in a storm) or “to erode” (as in a rock).
- “Weedy” can mean “overgrown” (“The garden is weedy”) or stunted (“The boy looks weedy”).
- “Yield” can mean “to produce” (as in a chemical equation) or “to concede” (as in driving).
Source: http://en.wikipedia.org/wiki/Auto-antonym (also contains a good introduction to the phenomenon).
Many more examples!
Good blog post on this subject – also one that mentions Shakespeare’s use of words that contain opposite meanings within themselves.
Read Freud on this phenomenon: