Nag
Part of speech: noun
Definition: A small horse; a pony. An old useless horse. One who nags.
Part of speech: verb
Definition: To bother with persistent memories. To repeatedly complain about often insignificant matters. To act inappropriately in the eyes of peers, to backstab, to verbally abuse.
Example sentence: In any awards ceremony, if you're a finicky person like myself, you can pick a multitude of things to nag about. I get frustrated with the comedy category because it feels like it gets sidelined a lot of the time for all kinds of things - not sidelined, marginalized.
Nagger
Part of speech: noun
Definition: one who nags