Classic lollipop with a "Mystery Flavor" flavor (6)

I believe the answer is:

dumdum

(Other definitions for dumdum that I've seen before include "idiot" , "Illegal soft-nosed bullet" , "Exploding type of bullet" , "Soft-nosed bullet that expands when it hits target" , "Mud upset twice for an expanding bullet" .)

I've seen this clue in The New York Times.

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