watch out for

watch out for (someone or something)

1. Be careful, aware, or watchful of someone or something that may cause one harm or distress. It's a beautiful region, but you have to watch out for some dangerous wildlife. Watch out for Mr. Henderson—I heard his class is brutal.
2. To be vigilant for the arrival of someone or something. Would you mind watching out for the mailman? I'm expecting a package today.
3. To take responsibility for or ensure the welfare of someone or something. My parents told me to watch out for my little brother as he starts his first year in high school.
See also: for, out, watch
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.

watch out for someone or something

 and look out for someone or something 
1. to be on guard for someone or something; to be on watch for the arrival or approach of someone or something. Watch out for someone wearing a white carnation. Look out for John and his friends. They'll be coming this way very soon.
2. and look out; watch out Fig. to try to avoid a confrontation with someone or something. Watch out! That car nearly hit you! Look out for John. He's looking for you, and he's really mad. Thanks. I'd better look out.
See also: for, out, watch

watch out for someone

 and look out for someone
Fig. to watch over and care for someone. When I was a kid, my older brother always watched out for me. I really needed someone to look out for me then.
See also: for, out, watch
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.
See also:
References in periodicals archive ?
Watch out for: Andrew Crook, a powerful batsmen in the manner of Andrew Symonds and Sajid Mahmood, England's next fast bowler.
Watch out for: Stuart Broad, who has it in him to be a Test player.
Watch out for: Eoin Morgan, who will, perhaps, develop into the finest batsman produced by Ireland, and Wright, a quickish bowler with some skill.
Watch out for: Worcestershire imports, Peters and Wigley.
Watch out for: Deon Kruis and Tim Bresnan could form a dangerous bowling partnership.
Watch out for him in the Group 2 Sandown Mile next Saturday.