Synonyms of adventitious

2 Syllables
chanced, lucky, random, breezer, driftless, luckiest, casual, foreign, chancing, chancer, fluker, luckier, cincher
3 Syllables
objectless, possible, unaimed, extraneous, unplanned, fortuitous, extrinsic, by-the-way
4 Syllables
adscititious, incidental, nonessential, supervenient, aleatory, accidental
5 Syllables
serendipitous
6 Syllables
unassimilable