consensual adj.

c. 1300, "agree, give assent; yield when one has the right, power, or will to oppose," from Old French consentir "agree; comply" (12c.) and directly from Latin consentire "agree, accord," literally "feel together," from assimilated form of com "with, together" (see con-) + sentire "to feel" (see sense (n.)).

"Feeling together," hence, "agreeing, giving permission," a sense evolution that apparently took place in French before the word reached English. Related: Consented; consenting.

suffix forming adjectives from nouns or other adjectives, "of, like, related to, pertaining to," Middle English -al, -el, from French or directly from Latin -alis (see -al (2)).

also nonconsensual, "done without consent," by 1945 in legalese, from non- + consensual (q.v.). Used since 1960s by sociologists and in political science; used by 1977 in legal discussions and definitions of rape and other sex crimes and popularized in this sense from c. 1995. An earlier adjective was non-consenting (1670s), which was used of persons, not acts.