Definition

1. Adjective:
   • Based on supposition rather than fact or evidence: Describes something that is assumed, hypothesized, or taken for granted without conclusive proof. It implies a lack of solid foundation in reality or verifiable data.
   • Hypothetical or conjectural: Pertaining to an idea, scenario, or entity that is proposed for the sake of argument or explanation but is not necessarily true or real.

Usage and Examples

• General Use:

  • The entire argument was built on a suppositious premise, so its conclusions were unreliable.
  • Her account of the event was dismissed as suppositious by the investigators, who demanded concrete evidence.

• In Academic/Scientific Context:

  • Many early scientific theories were suppositious, later to be confirmed or refuted by experimentation.
  • The paper warned against drawing firm conclusions from such suppositious data.

Advanced Usage and Nuances

• "Suppositious" vs. "Supposed": While both relate to assumption, "suppositious" often carries a stronger connotation of being unfounded, speculative, or even counterfeit. "Supposed" can be more neutral (e.g., ).
• In Legal or Historical Analysis: Used to describe documents, claims, or identities whose authenticity is in doubt.
  • The historian treated the newly discovered diary as a suppositious document until it could be authenticated.

Variants and Related Words

• Supposition (n): An idea or theory that is assumed to be true without proof; a hypothesis.
  • His plan was based on the supposition that funding would be available.
• Supposititious (adj): Often used interchangeably with "suppositious," but can more specifically imply something fraudulently substituted or spurious.
  • The will was declared invalid due to supposititious signatures.
• Conjectural (adj): Based on incomplete information; guesswork.
• Hypothetical (adj): Based on a suggested idea or theory for the sake of argument or investigation.

Synonyms

• Conjectural
• Hypothetical
• Speculative
• Presumptive
• Theoretical
• Assumed

Antonyms

• Factual
• Certain
• Verified
• Proven
• Authentic
• Genuine

Idiomatic Expressions and Phrases

• To rest on a suppositious foundation: To be based on unproven assumptions.
  • The policy's success rests on a suppositious foundation, ignoring key economic realities.
• A suppositious case: A scenario constructed for illustrative or argumentative purposes.
  • Let's consider a suppositious case where the treaty is never signed.

Adjective

1. based primarily on surmise rather than adequate evidence
   • theories about the extinction of dinosaurs are still highly conjectural
   • the supposed reason for his absence
   • suppositious reconstructions of dead languages
   • hypothetical situation