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!
    • 2011 February 1, Phil McNulty, “Arsenal 2 - 1 Everton”, in BBC[1]:
      Wilshere then opened up Everton's defence, but Van Persie lifted his finish over the onrushing Howard and also over the bar.
  2. (intransitive) To reveal oneself; to share personal information about oneself; to become communicative.
    After three hours of questioning, he finally opened up.
  3. (intransitive) To commence firing weapons.
    As the convoy entered the pass, we opened up on them with everything we had.
  4. (intransitive, figuratively, of the sky) To rain.
    The sky has really opened up. I've never seen this much rain!
  5. 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.