adj. 25B6; adjective
an accidental meeting : FORTUITOUS, chance, adventitious, fluky, coincidental, casual, serendipitous, random; unexpected, unforeseen, unanticipated, unlooked-for, unintentional, unintended, inadvertent, unplanned, unpremeditated, unthinking, unwitting.
the location is accidental and contributes nothing to the poem : INCIDENTAL, unimportant, by the way, by the by, supplementary, subsidiary, subordinate, secondary, accessory, peripheral, tangential, extraneous, extrinsic, irrelevant, non-essential, inessential.
intentional, deliberate.