chancy, chanceful, dicey, dodgy -- (of uncertain outcome; especially fraught with risk; "an extremely dicey future on a brave new world of liquid nitrogen, tar, and smog"- New Yorker)
chancy, fluky, flukey, iffy -- (subject to accident or chance or change; "a chancy appeal at best"; "getting that job was definitely fluky"; "a fluky wind"; "an iffy proposition")