The antonyms for the phrase "art loyal to" would be any words that convey disloyalty or betrayal. These could include terms like treacherous, false, insincere, disloyal, or betraying. The concept of being loyal to one's art suggests a deep devotion to a particular creative pursuit, but the antonyms for this phrase call into question the sincerity of that commitment. These words can be used to describe creative works that feel shallow or gimmicky, or they could refer to artists who are only interested in making money or gaining fame. Ultimately, those who are loyal to their art are those who create works that are authentic and heartfelt, regardless of the opinions of others.