could
Definitions
Used as the past tense of can, indicating ability or permission in the past.
Used to express possibility or uncertainty.
Used to make a polite request or suggestion.
Examples
I could hear the faint sound of music coming from the next room.
If you have time, could you please help me with this project?
We could go to the beach if the weather stays sunny tomorrow.
Synonyms
might may can potentially possibly was able to had the ability to
Antonyms
cannot could not was unable to lacked the ability to impossible