More incoherent male did rue getting drunk (7)
I believe the answer is:
muddier
'more incoherent' is the definition.
'male did rue getting drunk' is the wordplay.
'male' becomes 'm' (common abbreviation).
'getting drunk' indicates an anagram.
'did'+'rue'='didrue'
'didrue' with letters rearranged gives 'uddier'.
'm'+'uddier'='MUDDIER'
(Other definitions for muddier that I've seen before include "More confused" , "More obscure" , "Less clear" .)