Contronyms

Can A Word Be Its Own Opposite?

Yes! They are called Contronyms—words that are their own antonyms, depending on usage.
Here are a few examples

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

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

 Off :
can mean both ‘activated’ and ‘deactivated’.
Eg:- “Set off” - Activated
   “ Switch off - Deactivated

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

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

Sanction
can mean both ‘a penalty for disobeying a law’ and ‘official permission or approval for an action.