na-adjective, noun
Describes a person, lifestyle, or occupation that is law-abiding and socially respectable, often contrasted with the underworld or shady professions.
彼は堅気の商売をしている。
He runs an honest business.
堅気な人には手を出すな。
Don't mess with decent people.
noun, noun which may take the genitive case particle 'no'
respectable occupation; person with a respectable job
Specifically refers to a job or person outside the criminal or red-light districts; often used in contrast with yakuza or sex workers.
彼はヤクザから足を洗って堅気になった。
He left the yakuza and became a law-abiding citizen.
堅気の職に就きたい。
I want to get a respectable job.
Compound of 堅 (かた, 'firm, solid') and 気 (き, 'spirit, nature'), with rendaku voicing to ぎ. The literal sense of 'solid character' evolved to mean a person or occupation that is honest and law-abiding, especially in contrast to the criminal underworld.