From Longman Dictionary of Contemporary Englishlive by your witslive by your witsDISHONESTto get money by being clever or dishonest, and not by doing an ordinary job → live
Examples from the Corpus
live by your wits• The city's homeless live completely by their wits.• Days when there were no news sensations the newsboys lived by their wits.• Freddie lived by his wits and he was involved with many shady characters. 