Prepare to pop the question (5)
I believe the answer is:
kneel
'prepare to pop the question' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for kneel that I've seen before include "Assume humble posture" , "Go down on bended legs" , "Crouch down" , "Rest on hassock" , "Show obeisance" .)