foment UK /fəʊˈmɛnt/US /foʊˈmɛnt/verb 2noun 1forms 4 verb2 •To incite or cause troublesome acts; to encourage; to instigate.He was arrested for fomenting a riot; after all, it's bad enough being in a riot but starting one is much worse.Foreign governments have tried to foment unrest. •To apply a poultice to; to bathe with a cloth or sponge.Sties in the eye are irritating and disfiguring. Foment with warm water; at night apply a bread-and-milk poultice. — 1876 noun1 •Fomentation.He came in no conciliatory mood, and the foment was kept up. — 1892 formsfomented · fomenting · fomenteth · foments