adventive

adjective

1. not native and usually not yet well established, as exotic plants or animals.

noun

2. an adventive plant or animal.

adjective

1. (of a species) introduced to a new area and not yet established there; exotic

noun

2. such a plant or animal

1. Not native to and not fully established in a new habitat or environment. An adventive plant may be locally or temporarily naturalized without finding conditions that allow it to spread more widely.