Based on presumption, probability, conjecture, hypothesis or belief. / Making presumptions; behaving as one who presumes, who assumes that which they perhaps should not.

The condition of being presumptive.

In a presumptive manner / As is presumed to be the case

plural of presumption

the act of presuming, or something presumed / the belief of something based upon reasonable evidence, or upon something known to be true / the condition upon which something is presumed

Someone who will become an heir (usually to a monarchy) only if no-one with a higher-ranking claim is born.

plural of heir presumptive

(law) A matter that is deemed by law to be true, and therefore provides no opportunity for evidence to the contrary to be presented.

plural of conclusive presumption

(law) presumption of a fact that arises from proof of circumstances which necessarily attend such facts.