man of affairs; businessperson; administrator
Refers to a person skilled in practical business or administrative matters, often with a connotation of being efficient and worldly. Somewhat formal and not an everyday term; 実務家 is a more common near-synonym.
He is an excellent man of affairs and handles the company's operations single-handedly.
Compound of 事務 (business, office work) and 家 (person, expert). The exact historical derivation is uncertain, but the word follows a standard pattern for forming agent nouns.