without a basis in reason or fact; "baseless gossip"; "the allegations proved groundless"; "idle fears"; "unfounded suspicions"; "unwarranted jealousy"

Groundless, without reason or provocation.

unjustified, uncalled-for

To present participles which come from intransitive verbs, or are themselves employed as adjectives, to mark the absence of the activity, disposition, or condition implied by the participle;

lacking justification or authorization; "unreasonable searches and seizures"; "desire for undue private profit"; "unwarranted limitations of personal freedom"

Not warranted; being without warrant, authority, or guaranty; unwarrantable.

incapable of being justified or explained