A young dog, especially before sexual maturity (12-18 months)
"The energetic puppy chased its tail until it tripped over its own legs."
In plain English: A puppy is a young dog that has not yet grown into an adult.
"The new puppy chased its tail all afternoon."
Usage: Use the noun form when referring specifically to a young dog under 12-18 months of age rather than an adult canine. The verb sense, meaning to give birth to puppies, is rarely used in everyday conversation and should be avoided unless discussing animal breeding directly.
To bring forth whelps or give birth to pups.
"The old sheepdog will soon begin to puppy again after she gave birth last spring."
In plain English: To puppy means to act cute and innocent on purpose to get attention or sympathy from someone else.
"The kitten began to pounce and play with its owner's shoelaces like an energetic puppy chasing toys."
The word puppy likely entered the language in the 15th century as a term for "a woman's pet dog," probably borrowed from the French words poupée or popée, which meant doll or puppet. It eventually replaced the native English word whelp, though that older term survives today mostly to describe an ungrateful person rather than a young animal.