Nag /(năg)/

Nag

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

Nag

v. t. & i.

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.]

Nag

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