Ignore everything they say or do, and they will most likely quit pestering you eventually. Be truthful. If this doesn't work and the arrogant person continues to irritate you, tell them that you believe they are being arrogant and express your true feelings. Hopefully, they will take their attitude down a few notches once they realize what they're doing to you. The only way to deal with someone who is both cocky and arrogant is to ignore them. It may be difficult at first, but as soon as they get in your face, you have officially let them go too far. They will most likely back off after that since they know there's nothing good coming from arguing with you. If, however, they continue to be rude then tell them how you feel. Maybe they won't change right away, but at least they'll know why you had enough of them.