do (one's) darnedest(redirected from do his darnedest)
do (one's) darnedest
To put forth the utmost amount of energy or effort toward some task or goal. A more polite version of "do one's damnedest." Money is a little tight at the moment, but I'll do my darnedest to be there for your wedding.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.