This is the 13738th most frequent Turkish word.
kıl
Hair or fur.
Here, 'kıl' is used as an idiomatic expression to mean 'insignificant' or 'trivial', paired with 'tüy' (hair) to enhance the meaning of pettiness.
Kıl tüy ile uğraşmayı bırak.
Stop dealing with trivial matters.
In this sentence, 'kıl' is used to literally mean 'hair', discussing a medical condition related to hair.
Kıl dönmesi oldukça ağrılı olabilir.
Ingrown hair can be quite painful.
Here, 'kıl' is used informally to describe something as 'tricky' or 'complicated', indicating annoyance or difficulty.