Stressed about curl (5)
I believe the answer is:
tress
'curl' is the definition.
(I've seen this in another clue)
'stressed about' is the wordplay.
'about' says the answer is hidden in the clue (the clue goes around or about the answer).
'TRESS' can be found hidden inside 'stressed'.
(Other definitions for tress that I've seen before include "Rests (anag.)" , "Bit of hair" , "is a bit of a shock" , "Switch" , "Curl - lock" .)