Tammy's out of turn, but may do a good deed (5)
I believe the answer is:
scout
'do a good deed' is the definition.
'scout' can be an answer for 'do' (thesaurus). I'm not certain of the 'a good deed' bit.
'tammy's out of turn but' is the wordplay.
I cannot quite see how this works, but
'of' could be 'o' and 'o' is found within the answer.
'turn' could be 'cut' (cutting is a kind of turning) and 'cut' is found in the leftover letters.
A single letter 's' remains which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
'may' is the link.
Can you help me to learn more?
(Other definitions for scout that I've seen before include "Information-gathering soldier" , "One on a recce mission" , "Soldier on a recce mission" , "Talent seeker - boy on a jamboree" , "Person sent out to gain information" .)