reason
rea-son
noun
A cause, explanation, or justification for an action, event, or belief.
"What was the reason for his absence?"
noun
The faculty of thinking logically, forming judgments, and drawing conclusions.
"Humans possess the power of reason."
verb
To think, understand, and form judgments logically and rationally.
"She tried to reason with him."
Thesaurus
Synonyms: reasonableness, rationality, argue, grounds, cause, reason out, conclude, intellect, understanding, occasion, ground