intervenient

[ in-ter-veen-yuh nt ]
/ ˌɪn tərˈvin yənt /

adjective

intervening, as in place, time, order, or action.
incidental; extraneous.

noun

a person who intervenes.

Origin of intervenient

1595–1605; < Latin intervenient- (stem of interveniēns) coming between, present participle of intervenīre. See intervene, -ent