I don't think your idea is an impossibility, but there are several obstacles to overcome.No creo que tu idea sea imposible, pero hay varios obstáculos que superar.
(f) significa que un sustantivo es de género femenino (p. ej. la mujer, la luna).
(F)
In his boundless idealism, Garrett failed to see the impossibility of his ambitions.Con su infinito idealismo, Garrett no alcanzaba a ver la imposibilidad de sus ambiciones.