Exist as male insect, or biblical monster? (8)
I believe the answer is:
behemoth
'biblical monster?' is the definition.
(monster mentioned in the Book of Job)
'exist as male insect' is the wordplay.
'exist as' becomes 'be'.
'male' becomes 'he'.
'insect' becomes 'moth' (moth is a kind of insect).
'be'+'he'+'moth'='BEHEMOTH'
'or' is the link.
(Other definitions for behemoth that I've seen before include "Huge animal as from the Bible" , "Huge or monstrous person or thing" , "Monster" , "Giant" , "Monstrous beast (Job)" .)