Retch (5)

I believe the answer is:
heave
'retch' is the definition.
(heaving is a kind of retching)
This is the entire clue.
(Other definitions for heave that I've seen before include "Haul - retch" , "Lift or throw with great effort" , "Retch - lift using much effort" , "Pull hard; (sea) swell" , "Pull - retch" .)