"Art above board" means honest, transparent and ethical. Therefore, the antonyms for this phrase would be words that describe dishonest, deceptive or corrupt behavior. Some antonyms for "art above board" are deceitful, fraudulent, underhanded, crooked, shady, fraudulent, unethical and sneaky. These words describe actions that lack integrity and honesty, and that may seek to deceive or manipulate others. It is important to strive for transparency and honesty in all aspects of life, including business, relationships, and personal interactions. Being aware of antonyms for "art above board" can help individuals identify and avoid behaviors that undermine honesty and trustworthiness.