truant

The adjective and noun are derived from Middle English truant, truand, truaund (“(adjective) idle; tending to vagrancy (uncertain; may be a use of the noun); (noun) beggar; mendicant friar; vagrant, wanderer; worthless person, rogue, scoundrel; one who is absent without leave, truant; one who shirks duties”), from Old French truant, truand (“(adjective) beggarly; roguish; (noun) a beggar, vagabond; a rogue”) (modern French truand), probably of Celtic origin, possibly from Gaulish *trugan, or from Breton truan (“wretched”), from Proto-Celtic *taratrom, from Proto-Indo-European *térh₁-tro-m, ultimately from Proto-Indo-European *terh₁- (“to drill, pierce; to rub; to turn”).

Inherited from Middle English truaunten (“to obtain alms fraudulently; to behave like a rogue or scoundrel; to neglect a duty; to be idle or lazy”), and then partly:

from Old French truander (modern French truander (“to cheat, to con”)), from truand (noun) (see etymology 1) + -er (suffix forming infinitives of first-conjugation verbs); and

from Middle English truaunt (noun) (see etymology 1) + -en (suffix forming infinitives of verbs).