One young woman not quite right (5)
I believe the answer is:
amiss
'not quite right' is the definition.
(I've seen this before)
'one young woman' is the wordplay.
'one' becomes 'a' (a thing is one thing).
'young woman' becomes 'miss' (title for a young woman).
'a'+'miss'='AMISS'
(Other definitions for amiss that I've seen before include "Mistaken" , "Fallacious" , "Haywire" , "(Gone) wrong" , "Wrong - awry" .)