Main entry: open, open up
Definition: cause to open or to become open
Usage: Mary opened the car door
Main entry: open, open up
Definition: become open
Usage: The door opened
Main entry: open, open up
Definition: start to operate or function or cause to start operating or functioning
Usage: open a business
Antonyms: close, close down, close up, shut down, fold
Definition: cease to operate or cause to cease operating
Main entry: open up
Definition: talk freely and without inhibition
Antonyms: keep mum, dummy up, belt up, be quiet, shut up, clam up, close up, button up
Definition: refuse to talk or stop talking; fall silent