be crowded / be complicated / go into, go in / put into / become some state completely / do thoroughly / remain in the same state, such as remain sitting or remain silent

put away

carry into (often a sick or injured person to a hospital etc.)

sink

(idiomatic) to hold the key (to)

(colloquial) current boyfriend

(Internet slang) protected account (on social media, especially Twitter and Instagram)

to lock (a door, etc.) / (Internet slang) (of a SNS account) to change privacy setting to limited people and posts and/or profiles can be seen by limited people.

everything

black key (of a piano, etc.)