Wiktionary
n. 1 One who gnashes teeth. 2 A tooth.
Wikipedia
Gnasher is the pet dog of Dennis the Menace in the British comic strip Dennis the Menace from The Beano. First introduced in 1968, in issue 1363 dated 31 August 1968, seventeen years after Dennis the Menace started in The Beano. Dennis's first strip also featured a dog but this dog was unnamed and looked very different from Gnasher.
Gnasher was developed by Ian Gray (writer) and Davey Law (artist) from an original concept from staff writer Jim Fowler based on an article in a local newspaper about pets looking like their owners and/or vice versa. This article was used for a number of stories and led to the ongoing development of Gnasher and also the Bash Street Pups. As Davey struggled to picture the dog it was suggested he simply draw Dennis's hair and "put a leg on each corner and two eyeballs at that end". The result was one of the most enduring images for publishers DC Thomson. Soon after his introduction Gnasher's appearance changed from looking like Dennis' hair on legs to the more dog-like recognisable character he is today.
The G on the beginning of both Gnasher and his son Gnipper's names is not pronounced. Most of their speech bubbles also consist of normal English words beginning with the letter N with a silent G added to the beginning (e.g. Gnight, Gnight).
Usage examples of "gnasher".
He could walk up to any potential prey exhibiting the innocence of a young herbivore, before - at the last moment - revealing hostile gnashers with which to decapitate his unfortunate prey.
Gentlemen in their prime -- the owner of a large flour mill, a hotel-owner with his slightly rouged young friend, a nobleman high in the councils of an important business firm, a whole tableful of men's clothing manufacturers who were in town for a board meeting, the bald actor who was known in the Cellar as the Gnasher, because he gnashed his teeth when he wept -- all were in tears before the ladies joined in.
Scours those white gnashers good, with lots o' swishin' an' spit-tin'.
There were impact-dispersing skullcaps for the clumsy, disposable looparound mouthpieces for the tongue gnashers, lockfast maxi-Pampers for the thrashing incontinent, and countless kinds of medication reminders that beeped and buzzed and chimed to remind the forgetful.