Rule reminder
Review: in-/im-/ir-/il- (negation), ri- (again), s- (reversal), pre-/dis-/stra- (before/reversal/beyond), auto-/tras-/sovra- (self/across/over), -issimo (very), -ino/-etto (diminutive), -one/-accio (augmentative/pejorative), -abile/-ibile (capable of), -oso (full of), -mente (adverb), -aio/-ista (profession).
'Irragionevole' means: