Left Craig the damage, showing lack of energy (9)
I believe the answer is:
lethargic
'lack of energy' is the definition.
(I've seen this before)
'left craig the damage' is the wordplay.
'left' becomes 'L' (common abbreviation).
'damage' indicates anagramming the letters (I've seen 'damaged' mean this).
'craig'+'the'='craigthe'
'craigthe' is an anagram of 'ethargic'.
'l'+'ethargic'='LETHARGIC'
'showing' is the link.
(Other definitions for lethargic that I've seen before include "lack of energy" , "low in vitality" , "languid" , "Sluggish and apathetic" , "Enervated" .)