Learner's definition of PUPPY
— used in a playful way to refer to a thing
— used in a playful way to refer to a person
If they thought the new mayor would be easy to bribe, they picked the wrong puppy. [=the wrong guy]
That guy is one sick puppy. [=that guy is crazy, cruel, or disgusting]
I was one tired puppy [=I was very tired] after a long day of hiking.