Habit of guy, beginning to moan when interrupted by flipping alarm (9)
I believe the answer is:
mannerism
'habit' is the definition.
(thesaurus)
'guy beginning to moan when interrupted by flipping alarm' is the wordplay.
I cannot really see how this works, but
'guy' could be 'man' (guy can informally mean a man) and 'man' is present in the answer.
This explanation may well be incorrect...
'of' acts as a link.
Can you help me to learn more?
(Other definitions for mannerism that I've seen before include "Habitual way of behaving" , "Idiosyncrasy" , "peculiarity" , "Habitual gesture" , "Italian art?" .)