p's and q's

plural noun

ˌpēz-ᵊn-ˈkyüz 

1

: something (such as one's manners) that one should be mindful of

better watch his p's and q's when I get a six-gun of my own

—Jean Stafford

2

: best behavior

being on her p's and q's for two solid days was too much

—Guy McCrone

Word History

Etymology

from the phrase mind one's p's and q's, alluding to the difficulty a child learning to write has in distinguishing between p and q

First Known Use

1779, in the meaning defined at sense 1

Kids Definition

p's and q's

noun

ˌpēz-ᵊn-ˈkyüz 

: something (as manners) that one should be careful about

always minded my p's and q's around my aunts and uncles