Consumed in great enthusiasm (5)
I believe the answer is:
eaten
'consumed' is the definition.
(similar in meaning)
'in great enthusiasm' is the wordplay.
'in' indicates the answer is hidden within the clue.
'EATEN' can be found hidden inside 'great enthusiasm'.
(Other definitions for eaten that I've seen before include "What's taken in" , "This bread is soon forgotten, it's said" , "corroded" , "Upset" , "having enjoyed dinner?" .)