look out for number one

verb1

•
To act in one's own interests; to act in a manner advantageous primarily to oneself.
- "I'm a poor widder, Mr. Martin, and I must look out for number one. I can't afford to keep boarders that don't pay their bills." — 1870

forms

looked out for Number One · looked out for number one · looking out for Number One · looking out for number one · looks out for Number One · looks out for number one