dullen
To make something dull
G: You can probably shave your legs about 10 times with one of my mach 3 blades.
H: That's all?
G: Yeah.
H: Why?
G: Because every time you shave, it dullens the razor.
H: That's all?
G: Yeah.
H: Why?
G: Because every time you shave, it dullens the razor.