An act or gesture that is supremely generous, selfless, decent, or otherwise rad. The "yin" to a Dick Move's "yang". Used to highlight a moment where somebody has done something truly excellent to make other people's lives better.
I really needed to get away early, so Brady covered for me in my 4:00 meeting. Absolute muff move. Love that guy.
Remember when Stevo gave me his last smoke because I'd run out and the shops were shut? Muff move!