dodo – Comes from Portuguese doudo, “fool, simpleton,” from the bird’s awkward appearance. More…
doodle – Originally a noun meaning “fool, simpleton,” from German dudeltopf, it came to mean absent-minded scribbling. More…
gullible – A derivative of archaic gull, “dupe” or “simpleton.” More…
half-wit – Originally was “a would-be wit whose abilities are mediocre”; the sense of “simpleton” (one lacking all his wits) is attested to 1755. More…