Lethargy is moving too slow for the intended lead’s request (‘lead’ is the action, and not the person). What this really boils down to is the reaction time of the dancer that is a.) a lag from the time at which a request was sent to the time it was received. and b.) way in which it is done (the real speed issue). Note what’s missing from this definition, the roles of the dance! There is no blame in this definition. None what so ever. However, that is seemingly about to change. It’s not, but your perception of it will until you get to the end.