¹casual

accidental, fortuitous, casual, contingent mean not amenable to planning or prediction. accidental stresses chance <any resemblance to actual persons is entirely accidental>. fortuitous so strongly suggests chance that it often connotes entire absence of cause <a series of fortuitous events>. casual stresses lack of real or apparent premeditation or intent <a casual encounter with a stranger>. contingent suggests possibility of happening but stresses uncertainty and dependence on other future events for existence or occurrence <the contingent effects of the proposed law>.

random, haphazard, casual mean determined by accident rather than design. random stresses lack of definite aim, fixed goal, or regular procedure <a random selection of books>. haphazard applies to what is done without regard for regularity or fitness or ultimate consequence <a haphazard collection of rocks>. casual suggests working or acting without deliberation, intention, or purpose <a casual collector>.