Voluntarily forgo (5)
I believe the answer is:
'voluntarily forgo' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for waive that I've seen before include "Forgo right or claim" , "Don't insist on" , "Give up" , "Refrain from insisting on right or claim" , "Refrain from insisting on right or privilege" .)