frontera, f., frontier.
frugal, frugal.
frustrar, to frustrate.
fruta, f., fruit.
fuego, m., fire; poner —, to set fire (to); —s fatuos, ignis fatuus; will-o'-the-wisp.
fuelles, m. pl., bellows (of an organ); para darle á los —, to pump the bellows.
fuente, f., fountain, source.
fuer, á — de, as, like, being, by dint of being, since you are (or were).
fuera, out; — de, outside of, beyond, beside; — de sí, beside oneself.
fuerte, strong, mighty, violent.