c. 1400, nome, "deprived of motion or feeling, powerless to feel or act," literally "taken, seized," from past participle of nimen "to take, seize," from Old English niman "to take, catch, grasp" (from PIE root *nem- "assign, allot; take"). The unetymological -b (to conform to comb, limb, etc.) appeared 17c. The notion is of being "taken" with palsy, shock, and especially cold. Figurative use is from 1560s.
"to make numb, deprive of sensation or power of movement," 1550s (implied in numbed), from numb (adj.). Related: Numbing.