late 15c., from Old French sumptueux or directly from Latin sumptuosus "costly, very expensive; lavish, wasteful," from sumptus, past participle of sumere "to borrow, buy, spend, eat, drink, consume, employ, take, take up," contraction of *sub-emere, from sub- "under" (see sub-) + emere "to take, buy" (see exempt, adj.). Related: Sumptuously; sumptuousness.