"make merry, have fun, romp playfully," 1580s, from frolic (adj.) "joyous, merry, full of mirth" (1530s), from Middle Dutch vrolyc "happy," a compound of vro- "merry, glad" + lyc "like" (see like (adj.)). The first part of the compound is cognate with Old Norse frar "swift," Middle English frow "hasty," from PIE *preu- "to hop" (see frog (n.1)), giving the whole an etymological sense akin to "jumping for joy." Similar formation in German fröhlich "happy." Related: Frolicked; frolicking. As a noun from 1610s.