agelastic (adj. and n.) or agelast (n.)
"One who never laughs," "never laughing" (OED)
Marked as obsolete, but found in quite delightful current use in Jessica Milner Davis's "Farce," in which she defines slapstick as "physical but stylized beatings and the humiliation of agelastic targets" (3).
Wouldn't Agelast be a wonderful name for a somewhat Dickensian character (with a pun on a sort of unsmiling agedness or dusty agelessness)? What would it do to a child to be named "Agelast"?
There's a fascinating implication in Freud that the agelast, if such an one exists, can only be a person who is either mentally defective OR who has fully eliminated from his or her mind all remnants of belief in a God who communicates with his creation. (I arrive at this implication through analogy of the Comic with the Uncanny. Also I believe Freud also has something more direct to say about the agelast, but I can't remember it now.) We should talk more about this . . .
-JP