Roger the Shkiffler, a "white knuckle drunk" refers to an alcoholic who is not truly "recovering," but trying to tough it out (stay sober) without help. There is a huge community of alcoholics/addicts who believe strongly in twelve-step programs like AA, NA, etc. Over the years, these folk have developed their own jargon which can be confusing to someone not coming from that point of view. People who believe in such programs believe that their way is the only way to staying "clean and sober."