Alternative form of better the devil you know than the devil you don't know

(transitive, simile) To be intimately knowledgeable about something.

Used to allude to something unsaid or hinted at.

Alternative form of know like the back of one's hand

A phrase used to reply to a question whose answer the speaker doesn't want to reveal.

(colloquial) You are familiar with the situation I am describing; used to establish common ground with the interlocutor

(humorous) It is easy to conceal one's identity on the Internet.

(idiomatic) Synonym of know someone from Adam

To be unclear about what one is doing; to be bewildered.

Synonym of not know whether to shit or go blind (“be bewildered”).