(intransitive,reflexive,transitive) to open, open up
(transitive) to unlock
(transitive) to turn on
(transitive) to start, open, open up, set up (a business, restaurant, etc.)
(transitive) to crack, crack open, to pop (e.g., a safe, a bottle, a coconut)
(transitive) to break, break open, (new ground, a game, etc.); to break out (e.g., champagne); to breach
(transitive) to spread (one's legs, arms, fingers)
(figuratively,transitive) to answer (the door)
(pronominal) to open up (to become communicative)
(reflexive,slang) to leave, go away
(Latin-America,reflexive) to withdraw, back out of

the act of opening