A person who is overly enthusiastic or displays excessive cheerleading behavior, sometimes seen as superficial.

अतिउत्साही व्यक्ति

English Usage: She was such a rah-rah that her friends found her support to be a bit insincere.

Hindi Usage: वह इतनी अतिउत्साही थी कि उसकी दोस्तों ने पाया कि उसका समर्थन थोड़ा असत्य था।