(idiomatic) To substitute; to take somebody's place.

To attend a private meeting or class without participating.

(idiomatic) shove it up your ass (up yours) or back off. / Used other than figuratively or idiomatically: see sit on, sit, on, it.

A peaceful form of protest in which people occupy an area and refuse to leave.

Designed to be sat in.

present participle of sit in

Third-person singular simple present indicative form of sit in

plural of Sit

Third-person singular simple present indicative form of sit on it

present participle of sit on it