stick up verb5 •To be prominent; to point upwards.No matter how much I brush it, my hair always sticks up. •To speak or act in defence (of).Don't let them push you around, stick up for yourself. •To rob at gunpoint.I think they intend to stick up the bank. •To defy, to confront, to stand up to. •To maintain a commitment (as, to a proposition or role) formsstuck up · sticking up · sticks up