Sluggish, having to pull (3)
I believe the answer is:
lug
'pull' is the definition.
(I've seen this before)
'sluggish having' is the wordplay.
'having' indicates the answer is hidden within the clue.
'LUG' is hidden in the letters of 'sluggish'.
'to' acts as a link.
(Other definitions for lug that I've seen before include "Drag or carry with effort" , "Pull - ear" , "Drag, haul" , "A slangy ear" , "Carry with difficulty" .)