scold
n. countablen. a person who is very quick to criticize or find fault with others. You use this word for someone who is always pointing out mistakes or being negative.
n. a person who habitually criticizes or reproves others. Often carries a slightly pejorative or humorous tone in modern usage.
She is a bit of a scold when it comes to grammar.
The neighbor is a notorious scold who often complains about the noise from the new apartment.
While his intentions were to improve the team's performance, his constant nitpicking earned him the reputation of a scold among the younger players.
The noun is from Middle English scold(e), skald(e), first attested in the 12th or 13th century (as scold, scolde, skolde, skald). The verb is from Middle English scolden, first attested in the late 1300s. Most dictionaries derive the verb from the noun and say the noun is probably from Old Norse skald (“poet”) (cognate with Icelandic skáld (“poet, scop”)), as skalds sometimes wrote insulting poems, though another view is that the Norse and English words are cognate to each other and to Old High German skeltan (whence Modern German schelten (“to scold, chide”)), Old Dutch skeldan (whence Modern Dutch schelden (“to scold, berate”)), all inherited from Proto-Germanic *skeldaną (“scold”).