This is the 10354th most frequent Turkish word.
bilmezin
"Bilmezin" means "someone who does not know" or "ignorant person" in English.
Here, 'bilmezin' is used as a verb conjugated in the negative form for the third-person singular, indicating lack of knowledge.
O, bu konuları bilmezin.
They do not know about these topics.
In this sentence, 'bilmezin' is indicating a lack of awareness or knowledge, addressing the second-person singular.
Fikir bilmezin, bu yüzden yardım istemelisin.
You are unaware of the idea, therefore you should ask for help.
Here, 'bilmezin' is used to attribute a characteristic of unknowing to someone or something, functioning as a noun.