| verb | to believe especially on uncertain or tentative grounds “Scientists supposed that large dinosaurs lived in swamps” |
| verb | construct a theory about “Galileo theorized the motion of the stars” |
| verb | form or construct theories “he thinks and theorizes all day” |
| speculative | adjective | not based on fact or investigation |
| speculation | noun | a hypothesis that has been formed by speculating or conjecturing (usually with little hard evidence) |
| speculator | noun | someone who makes conjectures without knowing the facts |
| theorizer | noun | someone who theorizes (especially in science or art) |
| theory | noun | a belief that can guide behavior |
| theoriser | noun | someone who theorizes (especially in science or art) |
| theorisation | noun | the production or use of theories |
| conjecture | noun | reasoning that involves the formation of conclusions from incomplete evidence |
| hypothesis | noun | a message expressing an opinion based on incomplete evidence |
| supposition | noun | the cognitive process of supposing |
| supposal | noun | the cognitive process of supposing |
| theorization | noun | the production or use of theories |