c.1200, "beggar, vagabond," from Old French truant "beggar, rogue" (12c.), as an adjective, "wretched, miserable, of low caste," from Gaulish *trougant- (compare Breton *truan, later truant "vagabond," Welsh truan "wretch," Gaelic truaghan "wretched"), of uncertain origin. Compare Spanish truhan "buffoon," from same source. Meaning "one who wanders from an appointed place," especially "a child who stays away from school without leave" is first attested mid-15c.

"idle, loitering, given to shirking duty or business," 1540s, from truant, n..