Nag — Defs

01 n. A small horse; a pony; hence, any horse, especially one that is of inferior breeding or useless.

1.
A small horse; a pony; hence, any horse, especially one that is of inferior breeding or useless.
2.
A paramour; -- in contempt.[Obs.]

02 v. t. & i. To tease in a petty way; to scold habitually; to annoy; to fret pertinaciously.

imp. & p. p. Nagged; p. pr. & vb. n. Nagging

1.
To tease in a petty way; to scold habitually; to annoy; to fret pertinaciously.[Colloq.]

03 n. A person who nags, especially habitually; called also nagger.