Draw slowly or heavily (4)
I believe the answer is:
haul
'draw slowly or heavily' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for haul that I've seen before include "Drag; quantity of fish caught" , "(Of sailing ship) change course abruptly" , "Quantity taken (by fishermen?)" , "TRICK/TRICE" , "Spoils" .)