Numbing means taking away feeling from what it touches. A numbing cream, numbing cold, numbing pain.
A local anaesthetic blocks the nerve signal rather than the pain itself, which is why the area feels absent instead of comfortable. Figuratively, numbing means dulling the mind — mind-numbing tedium. Note numb, whose b is silent and was never pronounced in the modern word.
1adjectivenumbingTaking away feeling from what it touches.
“The dentist rubbed a numbing gel on my gum before the injection.”
numbing is a quality of deadening.
Proto-Indo-European
*nem-
English
numb
English, today
numbing
Built from
numb comes from the past participle of nim (“to take”). Compare German benommen (“dazed, numb”) and Old Norse numinn. The final ⟨b⟩ is a later addition; it was never pronounced, and did not appear in the original word.
Etymology from Wiktionary, CC BY-SA