“A Muggle. It’s what we call nonmagic folk like them. An’ it’s your bad luck you grew up in a family o’ the biggest Muggles I ever laid eyes on.”
-- Rubeus Hagrid (PS4)
Muggles, as non-magical folk are called by wizards, are “not as stupid as we think,” or so a report recently published in the Daily Prophet proclaimed (DP). Many witches and wizards find this concept hard to accept; Muggles are for the most part oblivious to the entire society of magical people which exists alongside their own.
Part of the reason for this is that Muggles simply don't believe that magic exists, which means they find non-magical reasons for the things that happen to them . Another part of the reason is that the Ministry of Magic works very hard to keep the Muggles in the dark. When a Muggle sees a dragon, for example, the Ministry sends operatives called Obliviators to useMemory Charms to make the Muggle forget all about it. The Ministry hides some wizarding places with Muggle-Repelling charms; this is why Muggles don't see Hogwarts for what it is. Many witches and wizards look upon Muggles kindly, but some see Muggles as nothing but a nuisance. The Ministry enforces a Muggle Protection Act to ensure that all of the wizarding world stays securely hidden from Muggle eyes. To most witches and wizards, Muggle society is essentially unknown. When they try to act like Muggles, the results can be humorous indeed. Hogwarts offers a class called Muggle Studies where students learn about the ways that Muggles live and how they survive without magic.
From the Web
Why don't muggle-born wizards use Muggle technology to fight Death Eaters? from scifi.stackexchange