Verb
look out for number one (third-person singular simple present looks out for number one, present participle looking out for number one, simple past and past participle looked out for number one)
(idiomatic) To act in one's own interests; to act in a manner advantageous primarily to oneself.
look out for Number One (third-person singular simple present looks out for Number One, present participle looking out for Number One, simple past and past participle looked out for Number One)
Alternative form of look out for number one