Put up with massive carnivore (4)
I believe the answer is:
bear
This might be a double definition.
'put up with' is the first definition.
(synonyms)
'massive carnivore' is the second definition.
'bear' can be an answer for 'carnivore' (bear is a kind of carnivore). I'm not sure about the 'massive' bit.
Can you help me to learn more?
(Other definitions for bear that I've seen before include "Large, shaggy-coated mammal" , "Carry or endure" , "Hold up" , "Put up with - beast!" , "Tolerate; animal" .)