stray

[1]	wander , roam , rove , range , straggle , drift , meander
[2]	deviate , roll , wander , diverge , wander , swan , tramp , digress , ramble , roam , cast , divagate , get/go off the track/subject , ramble , rove , go off on/at a tangent , get sidetracked , range , drift , vagabond
[3]	err , drift
[4]	digress , divagate , wander

[1]	straggler , vagrant , waif , (US) dogie

adj.

[1]	vagrant , lost , roving , roaming , wandering , homeless , derelict , abandoned
[2]	random , isolated , casual , chance , accidental , haphazard , singular , freak , accidental , unexpected
[3]	isolated , separate(d) , lone , odd , single