1. 
[syn: randomly, indiscriminately, haphazardly, willy-nilly, arbitrarily, at random, every which way]
2.  without having a choice; 
The Collaborative International Dictionary of English v.0.48:
Nill \Nill\, v. i.
   To be unwilling; to refuse to act.
   [1913 Webster]
         The actions of the will are "velle" and "nolle," to
         will and nill.                           --Burton.
   [1913 Webster]
   Will he, nill he, whether he wills it or not; usually
      contracted to willy-nilly.
      [1913 Webster]
WordNet (r) 3.0 (2006):
willy-nilly
    adv 1: in a random manner; "the houses were randomly scattered";
           "bullets were fired into the crowd at random" [syn:
           randomly, indiscriminately, haphazardly, willy-
           nilly, arbitrarily, at random, every which way]
    2: without having a choice