Willy-nilly (2,6)
I believe the answer is:
at random
'willy-nilly' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for at random that I've seen before include "Casually" , "willy-nilly" , "In no prearranged order" , "Indiscriminately" , "unplanned" .)