mid-15c., "youth, young man," from Middle French adolescent (15c.) or directly from Latin adolescentem (nominative adolescens) "growing, near maturity, youthful," present participle of adolescere "grow up, come to maturity, ripen," from ad- "to" (see ad-) + alescere "be nourished," hence, "increase, grow up," inchoative of alere "to nourish" (see old). Adolesce was a back-formed verb used early 20c. by H.G. Wells, G.B. Shaw, Louis MacNeice, but it seems not to have taken.