List of on to synonyms and on to related words.
alive to, appreciative of, apprised of, awake to, aware of, behind the curtain, behind the scenes, cognizant of, conscious of, hep to, in the know, in the secret, informed of, let into, mindful of, no stranger to, privy to, seized of, sensible of, sensible to, streetwise, undeceived, wise to