tall-it-all

A very tall person, like a know-it-all, except that the tall-it-all's smugness is expressed in derision at those shorter than they.

"Can you get that down for me?"
"Why, can't you get it?"
"No, I can't reach."
"Hey, not my fault you've got such a glaring physical deficiency."
"Quit being such a tall-it-all."