A person or thing that is outstanding, skillful, or of excellent quality; someone who is really good at what they do.
Possibly derived from 'crack' meaning 'excellent' (1800s slang) combined with 'jack' as a reference to a fellow or person. Some etymologists suggest connections to the word 'crack' meaning something that makes a sharp sound or breaks.
The brand name 'Cracker Jack' (the popcorn snack) was trademarked in 1896 and might have influenced or been influenced by this slang term for excellence, but the exact relationship remains one of those fun linguistic mysteries that historians still debate.
Complete word intelligence in one call. Free tier — 50 lookups/day.