willy-nil ‧ ly /ˌwɪli ˈnɪli/ BrE AmE adverb
[ Date: 1600-1700 ; Origin: will I nill I '(whether) I am willing (or) I am unwilling' ; nill 'to be unwilling' (11-19 centuries) , from Old English nyllan , from ne 'not' + wyllan ( ⇨ ↑ will 1 ) ]
1 . if something happens willy-nilly, it happens whether you want it to or not:
He found himself drawn, willy-nilly, into the argument.
2 . without planning, organization, or control:
Companies were accused of raising prices willy-nilly.