v. t. & i. [ imp. & p. p. Despumated p. pr. & vb. n. Despumating ] [ L. despumatus, p. p. of despumare to despume; de- + spumare to foam, froth, spuma froth, scum. ] To throw off impurities in spume; to work off in foam or scum; to foam. [ 1913 Webster ]