Stressed about plait (5)
I believe the answer is:
tress
'plait' is the definition.
(I know that plait can be written as tress)
'stressed about' is the wordplay.
'about' indicates a hidden word (the clue goes around or about the answer).
'TRESS' is hidden within 'stressed'.
(Other definitions for tress that I've seen before include "Rests (anag.)" , "Long lock or plait of hair" , "Bit of hair" , "is a bit of a shock" , "Braid of hair" .)