mere chance; accident; fortuity
not planned; random
by chance; casually
aimless, accidental, casual, offhand, careless, slipshod, incidental, unexpected, unthinking, unconscious, uncoordinated, slovenly, reckless, unconcerned, unpremeditated, loose, indiscriminate, unsystematic, unrestricted, unselected, irregular, motley, multifarious, blind, purposeless, unplanned, chaotic,
Antonyms; careful, studied, planned.
He always had a haphazard style one had never seen him make a plan.
This was it. She was finally going to exact her long-overdue revenge, a la Uma Thurman in Kill Bill. The threat was proved to be imaginary, however, when Taylor turned to a haphazard pile of vegetables.
The location of the examples in the sections is a bit haphazard as the section started to grow beyond my previous navigation options.