Don came down with pained cry (6)
I believe the answer is:
fellow
'don' is the definition.
(I've seen this before)
'came down with pained cry' is the wordplay.
'came down' becomes 'fell' (I've seen this in other clues).
'with pained cry' becomes 'ow' (I can't justify this - if you can you should give a lot more credence to this answer).
'fell'+'ow'='FELLOW'
Can you help me to learn more?
(Other definitions for fellow that I've seen before include "Relating to a person in the same situation as oneself" , "Companion or associate" , "Kind of associate, may be a traveller with communism" , "Colleague" , "Bloke; senior member of college" .)