A colloquial particle attached to the masu-stem of a verb to give a soft/encouraging imperative ("do ..."). It sounds gentler than more forceful imperatives.
遠慮しないで、食べなよ。
Don't hold back — go ahead and eat.
そんなに心配しないで、相談しなよ。
Don't worry so much — talk to me about it.
行きなよ、一緒に行こう。
Go on, let's go together.
A male-style prohibitive particle used after the plain form (as in "...するなよ") meaning "don't ..."; often rough or emphatic.
触るなよ！壊れるから。
Don't touch it! It will break.
そんなこと言うなよ、みんなの前で。
Don't say that, not in front of everyone.