do/try your damnedest

do your damnedest

INFORMAL, RUDE
If you do your damnedest to achieve something, you try as hard as you can to do it. I did my damnedest to persuade her. She was doing her damnedest to look as if she didn't care. Note: People sometimes use try instead of do. Ted tried his damnedest to explain things.
See also: damnedest

do (or try) your damnedest

do or try your utmost to do something.
The superlative form of the adjective damned is used here as a noun and can mean either ‘your worst’ or (more usually now) ‘your best’, depending on the context.
See also: damnedest

do/try your ˈdamnedest

(informal) try very hard; make a very great effort: He was doing his damnedest to make me feel uncomfortable so that I would leave.
See also: damnedest, try