The phrase "putting John Henry on" is usually used to mean tricking or deceiving someone. Antonyms for this phrase include being honest, straightforward, open, truthful, direct, sincere, transparent, or genuine. People who are honest and truthful don't have to put on a show or trick someone into believing something that isn't true. They can communicate clearly and directly, without any hidden motives or agendas. Being transparent and genuine is also important in building trust and authenticity in relationships. So, instead of putting John Henry on, it's always better to be honest and sincere with others.