Stop messing about! (6)
I believe the answer is:
behave
(Other definitions for behave that I've seen before include "Comport oneself" , "function" , "Act in a certain way" , "Conduct oneself properly" , "Mind your manners" .)
I believe the answer is:
behave
(Other definitions for behave that I've seen before include "Comport oneself" , "function" , "Act in a certain way" , "Conduct oneself properly" , "Mind your manners" .)