Slow to use the garlic (9)
I believe the answer is:
lethargic
'slow' is the definition.
(I've seen this before)
'use the garlic' is the wordplay.
'use' is an anagram indicator.
'the'+'garlic'='thegarlic'
'thegarlic' is an anagram of 'LETHARGIC'.
'to' is the link.
(Other definitions for lethargic that I've seen before include "Listless" , "Short of energy" , "reluctant to move" , "languid" , "Sluggish and apathetic" .)