Informal, and often a little teasing. If two people are palsy-walsy, they are acting very friendly — close, almost like best pals. Though actually, the speaker often does not quite like it, or does not quite believe it. The phrase can suggest the friendship is sudden, too sweet, or a bit fake: colleagues who were cold last week and are palsy-walsy today, or someone getting palsy-walsy with the boss. It has a jokey, slightly old-fashioned American ring; younger people may still understand it, but it sounds like something an older speaker would say with a raised eyebrow. It describes a manner, not a medical state.