ˈrēz ə nlə̇s adjective
Etymology: Middle English resonles, from reson, resoun reason + -les -less
1.
a. : not having the faculty of reason
a reasonless brute
b. : not marked by the use of reason : devoid of common sense : senseless
a reasonless hostility
2. : not based on or supported by reasons
an apparently arbitrary and reasonless change
• rea·son·less·ly adverb
• rea·son·less·ness noun -es