cracker

UK: /ˈkrækə^r/ US: /ˈkrækɚ/ ,(krak′ər)

WordReference Random House Learner's Dictionary of American English © 2025

crack•er /ˈkrækɚ/   n. [countable]

1. Food a thin, crisp biscuit.
2. a firecracker.

adj. [be/go + ~]

3. Computing crackers, Informal. wild;
   crazy:
   to go crackers from too much work.

WordReference Random House Unabridged Dictionary of American English © 2025

crack•er  (krak′ər), n. 

1. Food a thin, crisp biscuit.
2. a firecracker.
3. Also called crack′er bon′bon. a small paper roll used as a party favor, that usually contains candy, trinkets, etc., and that pops when pulled sharply at one or both ends.
4. Slang Terms (cap.) [Sometimes Disparaging and Offensive.] a native or inhabitant of Georgia (used as a nickname).
5. Slang Terms (disparaging and offensive). a poor white person living in some rural parts of the southeastern U.S.
6. Fish snapper (def. 5).
7. braggart;
   boaster.
8. a person or thing that cracks.
9. Chemistry a chemical reactor used for cracking. Cf. catalytic cracking, fractionator.

adj. 

10. Informal Terms crackers, wild;
    crazy:
    They went crackers over the new styles.

• 1400–50; late Middle English craker. See crack, -er¹; (defs. 4–5) perh. origin, originally in sense "braggart,'' applied to frontiersmen of the southern American colonies in the 1760s, though subsequently given other interpretations (compare corn-cracker); for crackers crazy, compare cracked, -ers

Collins Concise English Dictionary © HarperCollins Publishers::

cracker / ˈkrækə/ noun

1. a decorated cardboard tube that emits a bang when pulled apart, releasing a toy, a joke, or a paper hat
2. short for firecracker
3. a thin crisp biscuit, usually unsweetened
4. a person or thing that cracks
5. 
   another word for poor White
6. a thing or person of notable qualities or abilities
7. not worth a cracker ⇒ worthless; useless