disposition vs aptness

disposition and aptness both are nouns.

Word	Noun	Adjective	Verb	Adverb
disposition	Yes	No	No	No
aptness	Yes	No	No	No

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

disposition: a natural or acquired habit or characteristic tendency in a person or thing
aptness: a disposition to behave in a certain way

Other hyponyms of disposition include propensity, mordacity, predisposition, proneness, separatism, inclination, tendency.

disposition (noun)	aptness (noun)
the act or means of getting rid of something	appropriateness for the occasion
your usual mood	a disposition to behave in a certain way
a natural or acquired habit or characteristic tendency in a person or thing
an attitude of mind especially one that favors one alternative over others