Synonyms: reasonless, causeless
Definition: having no justifying cause or reason
Usage: a senseless, causeless murder; a causeless war that never had an aim; an apparently arbitrary and reasonless change
Similar words: unmotivated
Definition: without motivation
Synonyms: reasonless
Definition: not endowed with the capacity to reason
Usage: a reasonless brute
Similar words: irrational
Definition: not consistent with or using reason
Usage: irrational fears; irrational animals
Synonyms: reasonless, mindless, senseless
Definition: not marked by the use of reason
Usage: mindless violence; reasonless hostility; a senseless act
Similar words: unreasonable
Definition: not reasonable; not showing good judgment