ACT

(PERFORM) [verb] - to play (a part); to perform in a film, play, etc.Ellis Pike was chosen to act the part of the lawyer in the film. [T]Have you ever acted in a play before? [I]Have you ever acted this role? [T]I don't trust him - he always seems to be acting (a part) (= not being sincere). [I or T](figurative) Why are you always acting the (= behaving like a) fool/martyr? [T]If you act out something/act something out you express your thoughts, emotions or ideas as actions or behaviour.Children's negative feelings often get acted out in bad behaviour.