Don (3,2)
I believe the answer is:
put on
'don' is the definition.
(I know that don can be written as put on)
This is all the clue.
(Other definitions for put on that I've seen before include "Assume < present" , "in an unnatural way" , "Don clothes or stage play" , "Don; mount (a play)" , "Apply (to a surface) - present (on stage)" .)