A man friend, usually (8)
I believe the answer is:
normally
'usually' is the definition.
(synonyms)
'a man friend' is the wordplay.
'a man' becomes 'norm' (I can't explain this - if you can you should give a lot more credence to this answer).
'friend' becomes 'ally' (synonyms).
'norm'+'ally'='NORMALLY'
Can you help me to learn more?
(Other definitions for normally that I've seen before include "Mr Al Lyon? (anag)" , "Ordinarily, usually" , "in standard fashion" , "In the usual manner" , "In the usual or average situation" .)