slang for "feeble-minded person," by 1914, American English, from feeble. Other words used in the same sense were feeble (n.), mid-14c.; feebling (1887).
Entries linking to feeb
feeble adj.
late 12c., "lacking strength or vigor" (physical, moral, or intellectual), from Old French feble "weak, feeble" (12c., Modern French faible), a dissimilation of Latin flebilis "lamentable," literally "that is to be wept over," from flere "weep, cry, shed tears, lament" (from PIE *bhle- "to howl;" see bleat (v.)). The first -l- was lost in Old French. The noun meaning "feeble person" is recorded from mid-14c.
dweeb n.
1968, U.S. college student slang, probably a variant of feeb "feeble or feeble-minded person."