| unreliable(adjective, clear, strong, dependable) | |
| unsound(adjective, strong, sound, well) | |
| unsteady | |
| vague(adjective, clear, plain, definite) | |
| ambivalent(adjective, conflicting) | |
| arguable | |
| chancy(adjective, risky, dangerous) | |
| changeable(adjective, calm, constant) | |
| erratic(adjective, calm, unpredictable, consistent, wandering) | |
| fishy | |
| fluky(adjective, chance) | |
| hazy(adjective, confused) | |
| hesitant(adjective, uncertain, waiting) | |
| indecisive(adjective, uncertain, indefinite) | |
| indeterminate(adjective, uncertain, definite, vague) | |
| indistinct(adjective, obscure, ambiguous) | |
| mercurial | |
| moot | |
| opaque | |
| open(adjective, limited, restricted, undecided, hindered) |
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| APA | Smart Define. (2016). sure thesaurus. Retrieved September 23, 2026, from https://smartdefine.org/sure/thesaurus/antonyms |
| Chicago | Smart Define. 2016. "sure thesaurus" https://smartdefine.org/sure/thesaurus/antonyms (accessed September 23, 2026). |
| Harvard | Smart Define 2016, sure thesaurus, Smart Define, viewed 23 September, 2026, <https://smartdefine.org/sure/thesaurus/antonyms>. |
| MLA | Smart Define. "sure thesaurus" 31 March 2016. Web. 23 September 2026. <https://smartdefine.org/sure/thesaurus/antonyms> |