these words are used to express a low opinion of someone's intelligence

The classic alt.flame one-word epithet. Invented Words With Similar Meaning: fucknugget, fuckmonkey, fucksplash, fuckmunch, monkeyfuck, fuckling, fuckard, shitsneeze, nipplechips, scabscrotum, fuckburger, titling, titlet, bitchling, shitlet, shitling, bitchling, fuckwich, spankwich, shitball, spankard, foreskin-nose, pinky-butt, fuckstain, shitmunch, turdwipe, spermbelch, assbooger, fuckjuice, cheesedick. (This list is by no means complete.)

a stupid person; -- disparaging and vulgar.