Do a provocative act, as in an informal sort of shirt (5)
I believe the answer is:
tease
'do a provocative act' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how they can define each other.
'as in an informal sort of shirt' is the wordplay.
I cannot really see how this works, but
'as' is within the answer.
'shirt' could be 'tee' (tee shirt is a kind of shirt) and 'tee' is found in the leftover letters.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for tease that I've seen before include "Make fun of; comb wool" , "Gently mock" , "cause some irritation" , "Twit - flirt" , "Cod" .)