The phrase "was above board" means that something was legitimate, honest, and transparent. Its antonyms include words like dubious, dishonest, underhanded, deceitful, shady, and fraudulent. When something is said to be dubious, it is questionable or suspicious. Dishonest and deceitful refer to actions that are intended to deceive or cheat others. Underhanded and shady are often used to describe dealings that are secretive, immoral, or unethical. Fraudulent means that something is fake, false, or illegal. Therefore, knowing the antonyms of "was above board" can help you identify situations or individuals that may not be trustworthy or straightforward.