[adj] especially in the negative"no uncertain," as in"spoke in no uncertain terms"
[adj] not established beyond doubt; still undecided or unknown; "an uncertain future"; "a manuscript of uncertain origin"; "plans are still uncertain"; "changes of great if uncertain consquences"; "without further evidence his story must remain uncertain"
[adj] lacking or indicating lack of confidence or assurance; "uncertain of his convictions"; "unsure of himself and his future"; "moving with uncertain (or unsure) steps"; "an uncertain smile"; "touched the ornaments with uncertain fingers"
[adj] not certain to occur; not inevitable; "everything is uncertain about the army"; "the issue is uncertain"
[adj] not consistent or dependable; "an uncertain recollection of events"; "a gun with a rather uncertain trigger"
[adj] subject to change; "a changeable climate"; "the weather is uncertain"; "unsettled weather with rain and hail and sunshine coming one right after the other"
[adj] not established or confirmed; "his doom is as yet unsealed"
[adj] not safe from danger or mishap; "faced an uncertain future"; "an unsure existence"
[adj] not firm or secure; "balancing three boxes in an uncertain pile"
ambiguous, ambivalent, chancy, changeable, contingent, doubtful, dubious, flukey, fluky, groping, hesitant, iffy, incertain, indefinite, insecure, undependable, unreliable, unsafe, unsealed, unsettled, unsure, up in the air, variable