Delilah perhaps cut hair, bit upset (7)
I believe the answer is:
mantrap
'delilah' is the definition.
Both the definition and answer are singular nouns.
Perhaps you can see an association between them that I can't see?
'cut hair bit upset' is the wordplay.
'cut' means to remove the last letter.
'hair' becomes 'mane' (mane is a kind of hair).
'bit' becomes 'part' (both can mean a piece of something).
'upset' is a reversal indicator.
'part' back-to-front is 'trap'.
'mane' with its last letter removed is 'man'.
'man'+'trap'='MANTRAP'
'perhaps' is the link.
Can you help me to learn more?
(Other definitions for mantrap that I've seen before include "Seductress" , "something that ensnares folk" , "poacher may have been held" , "to catch trespassers" , "gin" .)