horrendo
/oˈrendo/ · B2 · adj
horrendous, horrific, dreadful, awful
👹😱 sounds like HORROR-endo: a horror ending, so horrendous
Horrendo comes from Latin horrendus, meaning 'to be shuddered at', from horrere (to bristle, shudder). It shares a root with English horror and horrid, so the Spanish word reads as horror plus an adjective ending.