Male snake gets angrier (6)
I believe the answer is:
madder
'angrier' is the definition.
('mad' can be similar in meaning to 'angry')
'male snake' is the wordplay.
'male' becomes 'm' (common abbreviation).
'snake' becomes 'adder' (type of snake).
'm'+'adder'='MADDER'
'gets' acts as a link.
(Other definitions for madder that I've seen before include "More disturbed - plant" , "Plant; more insane" , "Pigment" , "More wild; plant yielding red dye" , "More angry or frantic" .)