【口語】go to sea—it refers to someone who has given up a stable job to engage in business
下海
plunge into the commercial sea;go into business; become a professional actor (or actress)
那位老兄放棄公務(wù)員的差使，～經(jīng)商了。That fellow gave up his post in the public service and plunged into the commercial sea./票友～an amateur becoming a professional actor