usage: 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"
2. uncertain (vs. certain), indefinite, up in the air, indeterminate#1, undetermined
usage: 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 consequences"; "without further evidence his story must remain uncertain"
3. unsealed (vs. sealed), uncertain
usage: not established or confirmed; "his doom is as yet unsealed"
4. uncertain (vs. certain), chancy, fluky, flukey, iffy, contingent, up in the air, unpredictable
usage: not certain to occur; not inevitable; "everything is uncertain about the army"; "the issue is uncertain"