A short bristly moustache trimmed to a rectangular shape.
牙刷须，（修成长方形的）短髭
Example sentencesExamples
Oddly enough, in contrast with the bespectacled Cleverest Inventor who wears a loosely tied tie and untidy shirt, this astronomer is a public service type with a toothbrush moustache and a neat, dark suit.
And forget political correctness: William, the visiting brother of the British girl, does a hilarious Fawlty Towers-style imitation of the German boy, complete with Hitlerian toothbrush moustache and guttural accent.
He even cut his hair to resemble Hitler and grew a toothbrush moustache in a pathetic attempt to emulate his hero.
I don't think I was goosestepping along past Dixons and I haven't had a toothbrush moustache for years now.
There was no doubt in my mind that he'd have a toothbrush moustache, his hair plastered back, a fifties dinner jacket, with a dickie bow, and greying temples.
You never know, when I am drooling into my nightshirt in a bath chair, manhandled by warty nurses, I may sport a little shoe-polish-blackened toothbrush moustache and throw the odd Roman salute.