truant: [13] A truant was originally a ‘beggar’ or ‘vagrant’. The word was borrowed from Old French truant ‘vagabond’, which in turn came from Gaulish trugant- (amongst its Celtic relatives are Gaelic trudanach ‘vagabond’ and Welsh truan ‘wretched’). The word was not applied to absconding schoolchildren until the 15th century.
truant (n.)
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.
truant (adj.)
"idle, loitering, given to shirking duty or business," 1540s, from truant (n.).