Mind one's p's and q's

From Fresh Dictionary

English

Etymology

Disputed. See the alt.english.usage FAQ.

Verb

mind one's p's and q's (also mind your p's and q's)

1. ((idiomatic{{#if:|, {{{2}}}{{#if:|, {{{3}}}{{#if:|, {{{4}}}{{#if:|, {{{5}}}{{#if:|, {{{6}}}{{#if:|, {{{7}}}{{#if:|, {{{8}}}{{#if:|, {{{9}}}}}}}}}}}}}}}}}}})) To be very careful to behave correctly.