The word arrant intensifies. An arrant criminal is one heck of a criminal. Arrant nonsense is total nonsense.
Do you struggle for adequate superlatives? If so, you might want to add arrant to your arsenal. It can be used to add emphasis to other words, most often negative words. Arrant rudeness is extreme rudeness. Arrant hypocrisy is very hypocritical. An arrant liar is a world-class liar. Arrant has a meaning similar to complete or utter. Like other intensifiers, arrant turns up the volume on another word.