Does Snape have a bad hairstyle according to the wizarding world?

Question

Having read a lot of fanfiction, I just realized that the Potion Master's hair has never been described in a flattering manner. The phrase greasy-haired has been used to describe Severus Snape in most fanfiction where Snape is portrayed as an antagonist.

Does this common theme have an origin in canon?

The following are a few examples of such fanfic instances for your perusal.

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"I shall take your wisdom into consideration," Severus said neutrally.

"Also, try a different brand of hair shampoo."

A wry grin crossed Severus's face, and Harry thought it might have been, for the first time, that man's true smile. "Drop dead, Potter."

-_{Harry Potter and the Methods of Rationality}

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Answer 1

JKR is in the habit of giving readers a pen portrait of each character once per book, including a physical description. These tend to be fairly repetitive.

Professor Quirrell, in his absurd turban, was talking to a teacher with greasy black hair, a hooked nose and sallow skin.

_{^{HP and the Philosopher's Stone}}

and

Harry spun around. There, his black robes rippling in a cold breeze, stood Severus Snape. He was a thin man with sallow skin, a hooked nose and greasy, shoulder-length black hair, and at this moment, he was smiling in a way that told Harry he and Ron were in very deep trouble.

_{^{HP and the Chamber of Secrets}}

and

Snape approached their table, stared down his hooked nose at the roots, then gave Ron an unpleasant smile from beneath his long, greasy black hair.

_{^{HP and the Prisoner of Azkaban}}

etc etc