The term 'Rude One' can be defined by five different crossword solutions: STARER (6 letters), BOOR (4 letters), CAD (3 letters), LOUT (4 letters), and CHURL (5 letters). A STARER is someone who stares rudely or aggressively, a BOOR is a person who is rude and unmannerly, a CAD is a man who behaves dishonorably or disrespectfully, a LOUT is a person who is boorish and ill-mannered, and a CHURL is a person who is surly and bad-tempered. All of these words describe someone who is rude and offensive in their behavior.