illation vs presumption

illation and presumption both are nouns.

Word	Noun	Adjective	Verb	Adverb
illation	Yes	No	No	No
presumption	Yes	No	No	No

As nouns, presumption is a hyponym of illation; that is, presumption is a word with a more specific, narrower meaning than illation:

illation: the reasoning involved in drawing a conclusion or making a logical judgment on the basis of circumstantial evidence and prior conclusions rather than on the basis of direct observation
presumption: (law) an inference of the truth of a fact from other facts proved or admitted or judicially noticed

Other hyponyms of illation include analogy, corollary, derivation, deduction, entailment, implication, extrapolation.

illation (noun)	presumption (noun)
the reasoning involved in drawing a conclusion or making a logical judgment on the basis of circumstantial evidence and prior conclusions rather than on the basis of direct observation	a kind of discourtesy in the form of an act of presuming
	audacious (even arrogant) behavior that you have no right to
	an assumption that is taken for granted
	(law) an inference of the truth of a fact from other facts proved or admitted or judicially noticed