co-opt / kōˈäpt; ˈkōˌäpt/ • v. [tr.] (often be co-opted) appoint to membership of a committee or other body by invitation of the existing members. ∎ divert to or use in a role different from the usual or original one: social scientists were co-opted to work with the development agencies. ∎ adopt (an idea or policy) for one's own use: the green parties have had most of their ideas co-opted by bigger parties.DERIVATIVES: co-op·ta·tion / kōˌäpˈtāshən/ n.co-op·tion / ˌkōˈäpshən/ n.co-op·tive / -ˈäptiv/ adj.