means A young dog, or by extension any small or young animal — also a casual term for a youngster or, fondly, a cocky upstart.

from A shortening of 'puppy,' which arrived in English in the 1500s and is thought to come from the French 'poupée,' meaning 'doll' or 'plaything' (the same root that gives us 'puppet'). The thread is delightful: a puppy was, quite literally, a little living toy. Earlier English actually used 'whelp' for young dogs, and 'puppy' first carried a faintly mocking sense — a vain or foolish young person — before it settled into pure affection.