I. (ˈ)ad|ventiv, ədˈv- adjective
Etymology: Latin advent us (past participle) + English -ive
1. : not native : imperfectly naturalized : immigrant
an adventive weed
2. : arising in an unusual position : adventitious
• ad·ven·tive·ly adverb
II. noun
( -s )
: an exotic (as a plant) that is introduced often accidentally and imperfectly naturalized (as in being unable to bear fully mature fruit)