adventitious

The story

1. Latin · derived fromadventīcius“foreign, strange, accidental”
2. Medieval Latin · borrowed fromadventītius“coming from abroad, extraneous”
3. English todayadventitious

From Medieval Latin adventītius (“coming from abroad, extraneous”), a corruption of Latin adventīcius (“foreign, strange, accidental”), from adventus (“arrival, coming, approach, advent”) + -īcius (suffix forming adjectives), from adveniō (“to arrive”) + -tus (suffix forming action nouns).