monstruoso
/monsˈtɾwoso/ · B2 · adj
monstrous
👹 monstruo + -oso (full of) = full of monster → monstrous
Spanish monstruoso is built from monstruo (monster) plus -oso, a suffix meaning full of or having the quality of, like English -ous. So it describes something with monster-like qualities: huge, horrible, grotesque.