Carnivore heading for lair put on speed (5)
I believe the answer is:
ratel
'carnivore' is the definition.
(ratel is a kind of carnivore)
'heading for lair put on speed' is the wordplay.
'heading for' suggests taking the first letters.
'put on' means one lot of letters go next to another.
'speed' becomes 'rate' (rate is a kind of speed**).
The first letter of 'lair' is 'l'.
'l' after 'rate' is 'RATEL'.
(Other definitions for ratel that I've seen before include "one wanting honey" , "Honey badger" , "Honey-badger" , "creature with sweet tooth" , "Badger-like mammal" .)