Used to introduce, or alluding to, an apt adage.

(idiomatic, colloquial) suddenly, out of the blue.

(UK, Australia, New Zealand, South Africa, idiomatic, informal) To know; to be acquainted with (a person).

Alternative form of it takes one to know one

(idiomatic) To clearly understand one's own feelings, intentions, preferences, etc; to know precisely what one wants; to be decisive or determined.

Third-person singular simple present indicative form of know someone in the biblical sense

present participle of know someone in the biblical sense

(idiomatic) To have sex with someone.

(intransitive, idiomatic) To be experienced and knowledgeable. / (transitive, idiomatic) To be very familiar with; to have a significant understanding of.

Alternative form of know which end is up