participant (adj.)

"act or fact of sharing or partaking in common with another or others; act or state of receiving or having a part of something," late 14c., participacioun, from Old French participacion (13c.) and directly from Late Latin participationem (nominative participatio) "partaking," noun of action from past-participle stem of Latin participare "participate in, share in, partake of; to make partaker, to share, impart," from particeps (genitive participis) "partaker, comrade, fellow soldier," also, as an adjective, "sharing, partaking," from pars (genitive partis) "a part, piece, a division" (from PIE root *pere- (2) "to grant, allot") + -cip-, weak form of stem of capere "to take," from PIE root *kap- "to grasp." Related: Participational "involving or requiring participation" (1952).

"capable of participating; having the quality of participating," 1650s, from participate + -ive. Earlier adjectives were participate (from Latin participatus), participant, both late 15c.