Definitions
1.VerbTo rob at gunpoint."I think they intend to stick up the bank."
2.VerbTo be prominent; to point upwards."No matter how much I brush it, my hair always sticks up."
3.VerbTo speak or act in defence (of)."Don't let them push you around, stick up for yourself."
4.VerbTo defy, to confront, to stand up to.
5.VerbTo maintain a commitment (as, to a proposition or role)
6.VerbUsed other than figuratively or idiomatically: see stick, up. To put or post up by sticking."Stick up the postcard with a bit of tape."