Squib

A Squib is a non-magical individual born to at least one wizard or witch parent. They are considered the rare opposite of a Muggle-born witch or wizard, who possesses magical abilities despite having non-magical parents. While born into the wizarding world and aware of its existence, a Squib is unable to perform magic or attend Hogwarts School of Witchcraft and and Wizardry. The term itself reflects this, being an old wizarding world insult. Though they lack magical ability, Squibs are distinct from Muggles. They are able to perceive magical phenomena and locations that are normally hidden from non-magical eyes, such as Hogwarts castle and Dementors.

The status of a Squib in the wizarding world is often complicated and can be a source of disappointment or shame, particularly for old, Pure-blood families who prize magical lineage.

• Social Stigma: Squibs are often looked down upon. Aunt Muriel expresses disdain for Arabella Figg's status as a Squib, and Ron Weasley mentions his mother's second cousin was a Squib whom the family doesn't discuss, suggesting it is a sensitive subject. The Black family disowned Marius Black for being a Squib, scratching his name from the Black Family Tapestry.
• Integration: Some Squibs, like Argus Filch and Arabella Figg, live on the fringes of the wizarding world, taking on roles that do not require magic. Others choose to integrate fully into Muggle society. Ron Weasley mentions his great-aunt Muriel's Squib cousin became an accountant in the Muggle world.
• Legal Status: Squibs are registered by the Ministry of Magic. The existence of a Kwikspell course, advertised as a method for “Beginner's Magic” and aimed at Squibs, indicates that the Ministry is aware of them, although the course itself is shown to be completely ineffective.

• Lack of Magical Talent: The defining characteristic of a Squib is the complete inability to perform magic. They cannot cast spells, brew potions, or use a wand. Argus Filch's attempt to learn magic through the Kwikspell correspondence course proves futile. (J.K. Rowling has confirmed that potion-making always requires some wand-work, making it impossible for a Squib (Pottermore)).
• Magical Awareness: Unlike Muggles, Squibs can see and interact with the magical world. Arabella Figg was able to see the Dementors that attacked Harry Potter and Dudley Dursley in Little Whinging, a crucial piece of testimony in Harry's disciplinary hearing. She also bred part-Kneazle cats, demonstrating an ability to interact with magical creatures.

• Argus Filch: The caretaker at Hogwarts School of Witchcraft and Wizardry. His status as a Squib is a source of great bitterness for him.
• Arabella Figg: A member of the Order of the Phoenix who was tasked by Albus Dumbledore to watch over Harry Potter during his childhood on Privet Drive.
• Marius Black: A son of Cygnus Black II and Violetta Bulstrode, who was disowned from the Black family for being a Squib. He is seen blasted off the Black Family Tapestry in Number Twelve, Grimmauld Place.
• Molly Weasley's Second Cousin: An unnamed Squib who became an accountant. He is mentioned by Ron Weasley in conversation with Harry.
• Dolores Umbridge's Brother: Dolores Umbridge's younger brother was a Squib. Her father, a wizard, and mother, a Muggle, split up over this, with her mother and brother returning to the Muggle world. (Pottermore)
• Martha Steward II: The second child and only daughter of Ilvermorny founders Isolt Sayre and James Steward. Unlike her magical brothers, she was a Squib. (Pottermore)

In British English, a “squib” is a type of small, non-explosive firework that fizzes and burns out without a bang. The term is used metaphorically to describe a disappointing or failed outcome, making it a fitting, if derogatory, term for a child from a magical line who fails to develop magical powers.

• The existence of Squibs raises questions about the genetics of magic in the wizarding world. J.K. Rowling has stated that magic is a dominant and resilient gene. (J.K. Rowling interview)
• In the film adaptation of Harry Potter and the Chamber of Secrets, the envelope for the Kwikspell course is addressed to “Mr A. Filch”, confirming his identity as the one trying to learn magic. This reveal occurs differently in the novel, where Harry discovers a letter about the course in Filch's office.