fornido, -a, robust, thickset

fórmula, formula

fortalecido, -a, strengthened

fortaleza, strength, fortification

fortuna, fortune;
por ——, luckily

forzar, to force, violate, overthrow

forzosamente, necessarily

forzoso, -a, necessary, unavoidable, exacting

fosco, -a, frowning, dark, sullen

fosforescer, to be visible, phosphorescent