formidable, formidable, dreadful.
fórmula, f., formula, charm, recipe.
formular, to formulate, speak.
fornido, -a, robust, lusty, stout.
forraje, m., forage, hay, grass.
fortaleza, f., fortress, stronghold.
fortuna, f., fortune; por —, fortunately.
fosa, f., ditch, grave.
fosfórico, -a, phosphorescent.