numbnuts (plural numbnuts)
- (chiefly US, slang, derogatory, sometimes humorous) A slow-witted, unresponsive, or inept person (usually male).
- Tell numbnuts over there to wake up and pay attention to his work.
- (US, military, slang, derogatory) A recruit who is unintelligent or difficult to train.
- The drill instructor must have called him "numbnuts" fifty times today.
Usage notes 
"Numbnuts" is most commonly used as a form of address, as in "Hey, numbnuts!" However, the term sometimes has other noun functions, as in "I will defend you from numbnuts such as JamesM" ("The Big Gulp" by David Lansing, LA Times Calendarlive.com, 20 May 2007).
- “numbnuts” in Dictionary.com Unabridged, v1.0.1, Lexico Publishing Group, 2006.
- In A Dictionary of Slang: English slang and colloquialisms used in the United Kingdom, retrieved 25 May 2007.
- In An Unabridged Unofficial Dictionary for Marines, retrieved 25 May 2007.