adult (n.) Look up adult at Dictionary.com
"adult person," 1650s, from adult (adj.).
adult (adj.) Look up adult at Dictionary.com
1530s (but not common until mid-17c.), from Latin adultus "grown up, mature, adult, ripe," past participle of adolescere "grow up, mature" (see adolescent). As a euphemism for "pornographic," it dates to 1958 and does no honor to the word. In the old British film-rating system, A indicated "suitable for exhibit to adult audiences," and thus implicitly unsuitable for children (1914).