Here's what rhymes with unwarranted.

Consider these alternatives

unjustified / side unnecessary / very unjustifiable / viable unfounded / confounded unwise / size unfair / their undue / to counterproductive / productive intrusion / conclusion irresponsible / responsible uncalled / called arbitrary / very illogical / logical justified / side justify / high unsubstantiated / dated unseemly / extremely undeserved / first misguided / decided unconstitutional / constitutional unrealistic / characteristic imprudent / student untrue / you grossly / closely