do (one's) best(redirected from do their best)
do (one's) best
To do as well as one possibly can at something. I'm just not good at math, so, believe me, a B- in Algebra means that I've done my best. No, you're not the star player on the team, but you always do your best, which encourages the rest of us to do the same.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
do one's (level) best
to do something as well as one can. Just do your level best. That's all we can ask of you. Tom isn't doing his best. We may have to replace him.
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.
do one's best
Also, do one's level best or one's damnedest . Perform as well as one can, do the utmost possible, as in I'm doing my best to balance this statement, or She did her level best to pass the course, or He did his damnedest to get done in time. The first term dates from the 16th century, but the addition of level, here meaning "very," occurred only in the mid-1800s; the variant dates from the late 1800s.
The American Heritage® Dictionary of Idioms by Christine Ammer. Copyright © 2003, 1997 by The Christine Ammer 1992 Trust. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.