The Collaborative International Dictionary of English v.0.48:
Suppose \Sup*pose"\, v. t. [imp. & p. p. Supposed; p. pr. &
vb. n. Supposing.] [F. supposer; pref. sub- under + poser
to place; -- corresponding in meaning to L. supponere,
suppositum, to put under, to substitute, falsify,
counterfeit. See Pose.]
1. To represent to one's self, or state to another, not as
true or real, but as if so, and with a view to some
consequence or application which the reality would involve
or admit of; to imagine or admit to exist, for the sake of
argument or illustration; to assume to be true; as, let us
suppose the earth to be the center of the system, what
would be the result?
Suppose they take offence without a cause. --Shak.
When we have as great assurance that a thing is, as
we could possibly, supposing it were, we ought not
to make any doubt of its existence. --Tillotson.
2. To imagine; to believe; to receive as true.
How easy is a bush supposed a bear! --Shak.
Let not my lord suppose that they have slain all the
young men, the king's sons; for Amnon only is dead.
--2 Sam. xiii.
3. To require to exist or to be true; to imply by the laws of
thought or of nature; as, purpose supposes foresight.
One falsehood always supposes another, and renders
all you can say suspected. --Female
4. To put by fraud in the place of another. [Obs.]
Syn: To imagine; believe; conclude; judge; consider; view;
regard; conjecture; assume.
Moby Thesaurus II by Grady Ward, 1.0:
28 Moby Thesaurus words for "supposing":
allowing that, although, as if, as though, assuming that,
assumption, axiom, conjecture, guesswork, hypothesis, if,
inference, postulate, postulation, postulatum, premise,
presumption, presupposal, presupposition, proposition,
set of postulates, supposal, supposing that, supposition, surmise,
thesis, though, working hypothesis