nibbler

noun

1. Someone who nibbles (in various senses).

   “But whether unripe years did want conceit, / Or he refused to take her figured proffer, / The tender nibbler would not touch the bait, / But smile and jest at every gentle offer:”

   “The dog's lean, powerful body dashed down the hill. When the dust of his violence cleared, a sea of dirty white backs was wobbling up the hill, a black-and-white quickness darting now here, now there, straightening the line, hurrying a nibbler, urging a straggler.”

2. A tool for cutting sheet metal.
3. A fish of the sea chub subfamily Girellinae.
4. (historical)A program for copying floppy disks at a low level (typically one bit at a time) to circumvent protection systems.

   “A-Copier. MegaSoft, Ltd. Full Featured Nibbler.”

   “We used a program call Fast Hack 'Em. It had what was called a 'Nibbler'. It had the copy protection schemes for various games stored on one of the program disks, and you would load that up before copying the game. It then 'nibbled' away the protection from the data as it was copied.”