Definition of "open up"

open up

verb
third-person singular simple present opens up, present participle opening up, simple past and past participle opened up
1. (intransitive, transitive) To open.
  Quotations
  Wilshire then opened up Everton's defence, but Van Persie lifted his finish over the onrushing Howard and also over the bar.
  2011 February 1, Phil McNulty, “Arsenal 2 - 1 Everton”, in BBC‎
2. (intransitive) To widen.
3. (intransitive) To reveal oneself; to share personal information about oneself; to become communicative.
4. (intransitive) To commence firing weapons.
5. (intransitive, figuratively, of the sky) To rain.
6. To begin running, driving, travelling, etc., at maximum speed.
  Quotations
  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.
  1934, Henry G. Lamond, An Aviary on the Plains, Sydney: Angus and Robertson, page 211
7. (theater) Synonym of cheat out (“to face or turn toward the audience more than would be natural”)
  Quotations
  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.
  2015, Robert Barton, Acting: Onstage and Off, page 184