Middle English compound of ful "full" (see full (adj.)) + -som (see -some (1)). Sense evolved from "abundant, full" (mid-13c.) to "plump, well-fed" (mid-14c.) to "overgrown, overfed" (1640s) and thus, of language, "offensive to taste or good manners" (1660s). Since the 1960s, however, it commonly has been used in its original, favorable sense, especially in fulsome praise. Related: Fulsomely; fulsomeness.