hypothetical vs suppositional

hypothetical is a noun but suppositional is not a noun.

Word	Noun	Adjective	Verb	Adverb
hypothetical	Yes	Yes	No	No
suppositional	No	Yes	No	No

As adjectives, hypothetical and suppositional are synonyms defined as:

hypothetical and suppositional: based primarily on surmise rather than adequate evidence

Other synonyms of hypothetical include conjectural, divinatory, hypothetic, supposed, suppositious, supposititious.

hypothetical (noun)	suppositional (noun)
a hypothetical possibility, circumstance, statement, proposal, situation, etc.

hypothetical (adjective)	suppositional (adjective)
based primarily on surmise rather than adequate evidence	based primarily on surmise rather than adequate evidence