fleeting,transient,transitory,ephemeral,evanescent,flitting,flying,fading,momentary,short-lived,short,brief,passing,impermanent,fly-by-night,here today and gone tomorrow
a person who has escaped from a place or is in hiding especially to avoid arrest or persecution.
a route used by fugitive slaves
police have captured the fugitive gang leader
a fugitive from justice
he entertained a fugitive idea that Barbara needed him