The man grabs American behind large badger (6)
I believe the answer is:
hassle
'badger' is the definition.
(I know that badger is a more specific form of the action bedevil)
'the man grabs american behind large' is the wordplay.
'the man' becomes 'he' (he refers to a man).
'grabs' is an insertion indicator.
'american behind' becomes 'ass' (primarily US term for one's behind).
'large' becomes 'L' (eg in clothes sizes).
'ass'+'l'='assl'
'he' going around 'assl' is 'HASSLE'.
(Other definitions for hassle that I've seen before include "Modern word for bother and annoyance" , "Informal annoyance or quarrel" , "Informally, annoy or harass" , "Nuisance, bother" , "Bother, fuss" .)