What's the stupidest thing you've heard from an armchair commando, mall ninja, or COD fanboy? In person or the internet, as long as you were involved. Definition of armchair commando: An armchair commando is a lowlife nerd kid who sits at home shows off his military knowledge and argues about anything that has to do with military and politics involving military and pretends to know more than scientists do about ballistics, measurements, Parts of a weapon and more... Even though they have never shot a single gun ever in their life. Mall ninja: A term used in the firearm community to describe an individual who is obsessed with tactical, paramilitary style firearms and modifications, particularly firearms composed mostly of plastic. Such individuals are usually un-experienced novices who compulsively overpay for weapons and accessories not worth their weight in dog crap because such items looked cool in movies and video games.