Dog’s tons more fun, but not male (7)
I believe the answer is:
terrier
'dog's' is the definition.
(terrier is a kind of dog)
'tons more fun but not male' is the wordplay.
'tons' becomes 't'.
'more fun' becomes 'merrier' (I've seen this before).
'but not' suggests deleting specific letters.
'male' becomes 'm' (common abbreviation).
'merrier' with 'm' taken out is 'errier'.
't'+'errier'='TERRIER'
(Other definitions for terrier that I've seen before include "See 11" , "Dog bred for hunting" , "Breed of dog - volunteer soldier - estate register" , "(Yorkshire?) dog" , "Small, short-bodied dog" .)