Definition of uncertain

• 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"
• 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"
• not established or confirmed; "his doom is as yet unsealed"