dum-dum
n.— «When he returned in ’03, McLain was equipped with a thick cushion to wear atop his helmet (he refers to it as a “dum-dum”), which softened any potentially dangerous blows to the head.» —“McLain Making Progress” by Mitch Dobbs ‘Bama (Al.) June 24, 2004. (source: Double-Tongued Dictionary)
Further reading
An anadrome is a word that forms a whole new word when you spell it backwards. For example, the word “stressed” spelled backwards is “desserts.” Some people’s first names are anadromes. There’s the girl named Noel...
A flashlight doesn’t flash. It provides a steady beam of light. So why is it called a flashlight? The earliest versions lit up only briefly before the batteries gave out and required a recharge, so they were literally “flash lights...