conjectural
1. [ adjective ] based primarily on surmise rather than adequate evidence
Synonyms: suppositional suppositious supposititious divinatory supposed
Examples:

"theories about the extinction of dinosaurs are still highly conjectural" "the supposed reason for his absence" "suppositious reconstructions of dead languages" "supposititious hypotheses"

Related terms: theoretical
Similar spelling:   conjecture
  consecrate
  consecrated
  consecration