Faint cry curtailed by girlfriend (4,4)
I believe the answer is:
keel over
'faint' is the definition.
(I've seen this in another clue)
'cry curtailed by girlfriend' is the wordplay.
'cry' becomes 'keen' (I've seen this before).
'curtailed' means to remove the last letter.
'by girlfriend' becomes 'lover' (I can't justify this - if you can you should give a lot more credence to this answer).
'keen' with its last letter taken away is 'kee'.
'kee'+'lover'='KEEL OVER'
Can you help me to learn more?
(Other definitions for keel over that I've seen before include "Pass out" , "Fall, as in a faint" , "Capsize" , "Suddenly collapse" .)