Antonyms for the word "most sportspersonlike" could be "unsportsmanlike", "dishonest", "cheating", "unfair", "unethical", "unprincipled", "disgraceful", "disrespectful", "arrogant", "rudeness", "impoliteness". These words refer to behaviors and attitudes that go against the principles of sportsmanship and integrity in sports. Being sportsmanlike means demonstrating respect for one's opponents, following the rules and regulations of the sport, and maintaining spirit of fair play. On the contrary, unsportsmanlike conduct brings dishonor to oneself and one's team, undermines the spirit of the game, and damages the reputation of the sport.