grow a set (of balls)

grow a set (of balls)

rude slang To start acting in a strong, confident, or courageous manner, especially after having previously failed to do so. Though "balls" is a slang term for testicles, the phrase is not exclusively applied to males. Often used as an imperative. You need to grow a set of balls and ask your boss for a raise already! Janet, I know you're nervous about asking Tom out on a date, but just grow a set and give it a shot!
See also: grow, set
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.