Arbitrarily (2,6)
I believe the answer is:
at random
'arbitrarily' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for at random that I've seen before include "In no prearranged order" , "Indiscriminately" , "Haphazard" , "willy-nilly" , "without purpose" .)