Run off to wed (5)
I believe the answer is:
elope
'run off to wed' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for elope that I've seen before include "go off to the match?" , "Abscond for amorous purposes" , "Run away together" , "do a moonlight flit" , "Run away to Gretna Green?" .)