* Size: He is described as being very tall and broad, with a large frame.
* Face: He has a "wide, flat face" and a "bushy moustache" that is described as being "unruly".
* Hair: His hair is "thin and greasy" and usually "slicked back".
* Eyes: He has "small, beady eyes" that are often "shifty and nervous".
* Clothing: Gunther is usually seen wearing a "dark suit" and a "starched white shirt". He often has a "gloomy expression".
He's not described in detail, but the author, Lemony Snicket, makes it clear that Gunther is not a particularly pleasant or attractive individual. He is meant to be menacing and imposing, reflecting his role as Olaf's accomplice.
It's worth noting that the physical appearance of characters in A Series of Unfortunate Events can vary depending on the adaptation. In the Netflix series, Gunther is played by an actor named Donnell Rawlings, who presents a different interpretation of the character.