What is the Latin word for supposition?

The usual Latin words for “supposition” are opīniō, coniciō. The right choice depends on the sense; see the distinctions below.

English → Latin

“supposition” in Latin

opīniōopinion, conjecture, imagination, fancy, belief, expectation; reputation, esteem; report, rumor coniciōto throw or bring together, unite, connect; to throw, drive, force, hurl something; to dispatch, assign, make go

The English word supposition itself goes back to Latin suppōnō, through suppositio.

Riddle & Arnold A Copious and Critical English–Latin Lexicon, 1864

supposition

opinio: conjectura (conjecture); so by circumlocution with the verbs. A mere supposition, opinionis commentum: no third supposition is possible or conceivable, tertium nihil inveniri potest; tertium esse quidquam nego. Even on the supposition that; Vid: “even granting that,” in GRANT.

Quick answer

What is the Latin word for supposition?: The usual Latin words for “supposition” are opīniō, coniciō. The right choice depends on the sense; see the distinctions below.

Entry from J. E. Riddle & T. K. Arnold, A Copious and Critical English–Latin Lexicon (rev. C. Anthon, New York: Harper, 1864), digitised by Fergus J. P. Walsh, CC BY-SA 4.0; Latin markup adapted by latindictionary.co.