Contronyms

Can a word be its own opposite?

Yes!There are actually dozens of examples.They are called contronyms—words that are their own antonyms,depending on usage.

Here are a few for starters:

 Dust :
can mean ‘to add fine particles’ or ‘to remove fine particles’.

 Left:
can mean both
‘remaining’ and ‘departed’.

 Off:
can mean both ‘activated’ (as in set off) and ‘deactivated’.

 Oversight:
means both ‘watchful care’ and ‘an inadvertent error’.

 Screen :
 can mean both ‘to show’ and ‘to hide’.