Giving the high sign is a colloquialism that means to signal or communicate something discreetly or secretly. Its antonyms would be to communicate openly or transparently. Some relevant antonyms of giving the high sign include announcing, disclosing, proclaiming, and proclaiming. These terms imply that something important or significant is being communicated in a clear and direct manner, without any subterfuge or obfuscation. Antithetical words like dissembling, concealing, and hiding are also antonyms for giving the high sign because they suggest the opposite of being open and transparent in communication. In summary, giving the high sign is a covert or furtive way of communicating, whereas its antonyms refer to more forthright and explicit methods of communication.