Being cowardly, utter a loud cry of pain (6)
I believe the answer is:
yellow
'being cowardly' is the definition.
('yellow' can be similar in meaning to 'cowardly')
'utter a loud cry of pain' is the wordplay.
I cannot quite understand how this works, but
'utter' could be 'yell' (yelling is a kind of uttering) and 'yell' is present in the answer.
'of' could be 'o' and 'o' is present in the answer.
A single letter 'w' remains which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for yellow that I've seen before include "Name of river" , "Pusillanimous" , "Fearful - colour" , "Small European bunting" , "Sunny colour" .)