open up

open up (third-person singular simple present opens up, present participle opening up, simple past and past participle opened up)

1. (intransitive, transitive) To open.

   Some vacancies have opened up due to retirements.

   Open up the door!

   The executive pay gap is opening up again.

   • 2011 February 1, Phil McNulty, “Arsenal 2 - 1 Everton”, in BBC‎:

     Wilshire then opened up Everton's defence, but Van Persie lifted his finish over the onrushing Howard and also over the bar.

2. (intransitive) To widen.

   The corridor gradually opened up into a triangular room.

3. (intransitive) To reveal oneself; to share personal information about oneself; to become communicative.

   After three hours of questioning, he finally opened up.

4. (intransitive) To commence firing weapons.

   As the convoy entered the pass, we opened up on them with everything we had.

5. (intransitive, figuratively, of the sky) To rain.

   The sky has really opened up. I've never seen this much rain!

6. (intransitive) To begin running, driving, travelling, etc., at maximum speed.
   • 1934, Henry G. Lamond, An Aviary on the Plains, Sydney: Angus and Robertson, page 211:

     The pigeon is moving as before with unhurried haste. [...] But it must be all out. If it wasn't, then it would open up and get away from that shadow of death behind it.

7. (intransitive, theater) Synonym of cheat out (“to face or turn toward the audience more than would be natural”)
   • 2015, Robert Barton, Acting: Onstage and Off, page 184:

     In stage acting, we are frequently asked to cheat out to the audience by opening up our body positions so that we are something halfway between facing them and our partner.

8. (intransitive, oenology) Of wine: to develop its full flavor a short time after being uncorked and poured.

• unpope