First of all what are IV's?
IV's are short for "Individual Value's" and are key to determining your Pokémon's stats. IVs are randomly assigned when you encounter any wild Pokémon (or receive it as a gift or egg).
IVs consist of six stats: HP, Attack, Defense, Special Attack, Special Defense and Speed. Each range from 0-31 and the higher the number, the better your Pokémon's stat will be.
What are Perfect IV's?
Perfect IV's are when you have 31IV's in a particular stat or stats.
If a player says they have a 6 Prefect IV Pokémon what they're basically saying is that they have a Pokémon with 31IV's in each of their six stats: HP, Attack, Defense, Special Attack, Special Defense and Speed.
If they say they have a Pokémon with 5 Prefect IV's what they're basically saying is that they have a Pokémon with 31IV's in five of their six stats, the other stat may be 0-30.
