The term "un businesslike" refers to something that is not suited for a professional or work-related setting. Antonyms for this expression can be "practical," "effective," "organized," "competent," "efficient," "methodical," or "systematic." These words imply that a person or activity is well-suited for a job and can work effectively and efficiently in a professional environment. They suggest that someone is capable of adhering to established business practices, is capable of making sound decisions, and can work within a set of guidelines or frameworks. In summary, the antonyms for "un businesslike" convey qualities that are essential for success in the modern business world.