Consume in one attempt (3)
I believe the answer is:
eat
'consume' is the definition.
(eating is a kind of consuming)
'in one attempt' is the wordplay.
'in' indicates the answer is hidden within the clue.
'EAT' is hidden within 'one attempt'.
(Other definitions for eat that I've seen before include "Gobble up" , "Do cats - bats? Do bats - cats? (Alice in Wonderland)" , "Use a knife and fork" , "get stuck in" , "and 27: Be humiliated" .)