Everything flipping right in lemon fool (7)
I believe the answer is:
dullard
'fool' is the definition.
'everything flipping right in lemon' is the wordplay.
'everything' becomes 'all' (all things).
'flipping' is a reversal indicator.
'right' becomes 'r' (common abbreviation).
'in' is an insertion indicator.
'lemon' becomes 'dud' (both can mean a poor example of something).
'all' reversed gives 'lla'.
'lla'+'r'='llar'
'llar' put within 'dud' is 'DULLARD'.
(Other definitions for dullard that I've seen before include "simpleton" , "Boring type" , "Someone not very bright" , "Stupid fellow" , "Slow or stupid person" .)