Bad clues are mostly profane (7)
I believe the answer is:
secular
'profane' is the definition.
('secular' can be similar in meaning to 'profane')
'bad clues are mostly' is the wordplay.
'bad' is an anagram indicator.
'mostly' means to remove the last letter.
'are' with its last letter removed is 'ar'.
'clues' anagrammed gives 'secul'.
'secul'+'ar'='SECULAR'
(Other definitions for secular that I've seen before include "Lay" , "associated with those who are 21 [LAYMEN]" , "Layman's" , "Concerning the laity" , "Profane" .)