knock oneself out

1. Make a great effort, as in I was knocking myself out to finish on time . This expression also is put negatively, Don't knock yourself out , meaning “don't exert yourself; it's not worth that much effort.” [c. 1930]

2. Enjoy yourself, have a good time, as in You're off to Europe? Knock yourself out . [ Slang ; mid-1900s] Both usages allude to knocking oneself unconscious (see knock out ). For a synonym see break one's ass .

Related Words

• argue
• confront
• cope
• dispute
• go after
• grapple
• meet
• oppose
• push for
• resist
• vie