since puppy was taken from its littermates

since puppy was taken from its littermates and mother too early - it has missed out on very important socializing -- so when your adult dogs tries to let it know it doesn;t want to play - the pup doesn't understand ( because it was removed from its mom etc. too early) just monitor them and make sure the pup isn't pestering the adult too much... they will grow to be good friends i am sure