The Word is:”could”


modal verb: could

past of can1.
used to indicate possibility.
“they could be right”
used in making suggestions or polite requests.
“you could always ring him up”
used to indicate annoyance because of something that has not been done.
“they could have told me!”
used to indicate a strong inclination to do something.
“he irritates me so much that I could scream”

Source credit: Google