When a word means one thing, but also means its opposite, what you have is a contronym.
Contronym: a word having two meanings that contradict one another.
Contronyms aren’t the same as oxymorons, however, in which two contradictory terms are combined either mistakenly or for effect. The meaning of a contronym is understood by its use in context. Here are a few contronyms.
~Bolt can mean either to secure something or to flee something. For example:
She bolted the door. Or…She bolted out of there.
~Left can mean that something or someone remains or that someone or something left. For example:
John left the party. Or…As the party ended, John was the only one left.
~Overlook might mean to supervise something, but then again it might mean to neglect something. For example:
She overlooked the mistake the clerk made. Or…Karen carefully overlooked the transaction so no mistake was made.
~To sanction something means to approve of it, but it also means to punish or boycott something. For example:
Sam’s mother sanctioned his use of the car on Friday night. Or…Sam’s mother imposed sanctions upon him, including refusing him the use of the car on Friday night.
~To strike something means to hit it, or it might mean a swing and a miss. For example:
Bob bowled a perfect game on Saturday, striking every pin on the first attempt. However, he managed to strike out three times at his company softball game on Sunday.
Those are just a few examples of contronyms. Feel free to add comments with any more contronyms you can think of.
Aren’t words wonderful?