Meaning

noun a thin crisp wafer made of flour and water with or without leavening and shortening; unsweetened or semisweet

noun a poor White person in the southern United States

noun a programmer who cracks (gains unauthorized access to) computers, typically to do malicious things

originFrom Middle English craker (“a boaster”), equivalent to crack (“to break, snap, utter, make a sound”) + -er. From crack (verb), the sound made when one is broken. The hard "bread" and "biscuit" sense is first attested in 1739. The computing senses of cracker, crack, and cracking were promoted in the 1980s as an alternative to hacker, by programmers concerned about negative public associations of…

Etymology from Wiktionary, CC BY-SA 3.0