Puppy love is a noun used for the kind of romantic feelings that are had by children or adolescents. It is generally seen by adults as shallow or not real because the individuals are too young and do not have enough experience to understand ‘real love’. A couple common synonyms are first love or young love.
This term has been around since the 1800s, but is somewhat derogatory toward youth. Most of its modern usage, in print at least, is based in actual love for puppies.
The general explanation for the term is that everyone is inclined to love a puppy, who is small and cuddly, but the love wanes as the puppy turns into a dog with bigger problems.
Unlike puppy love which is listed in dictionaries, poppy love is a slang term. It can be used for the love of the poppy flower, which is red. Or the term is sometimes used to describe an addiction to heroin, made from a kind of poppy flower.
This slang is far from commonplace and should be used with caution. Most of the instances we found, in print, of this phrase were using poppy as the adjective form of the music genre of Pop and were describing a poppy love song.
Examples
Puppy love actually chips away at the triumvirate of tween psychological and social minefields. [Sun Sentinel]
A little puppy love during finals week is the relief of choice at Cedarville University. [WDTN]
Poppy love in Mumbai: Highs and lows of legal opium addicts [Hindustan Times]