Squib

From Fandom wank wiki

A squib is an individual in the Harry Potter novels who comes from a family of wizards but does not possess magical powers. (The word comes from British slang referring to a firecracker that doesn't explode.) In a sense, this is the opposite of a Muggleborn.

Examples of squibs in the novels include Argus Filch, Good King Nerdnor, and British Prime Minister Anthony Blair. A common misconception in Harry Potter fandom is that Ronald Weasley is a squib due to his low aptitude for magic, but this was disproven in Book 4 when it was revealed he is what the wizarding world calls a "dumbass."

The term is more notable due to its use in sorting communities to describe a rejected applicant. Now, nobody signs up for a chance to pretend to belong to an elite internet version of a fictional house at a made-up wizarding school to be told they don't have magical powers. Your typical Harry Potter fan has the self-image of being an unusually gifted wizard on par with Harry himself, so saying that s/h/it is little more than a no-magic-having background character is fightin' words. When you're squibbed, all at once you're busted down from Luke Skywalker to Jar Jar Binks. So, inevitably, squibbees wank.