How is “watch out for” used?

In All the President's Men (1976), one line is: “You know, my girlfriend told me to watch out for you.”

Which movie is “watch out for” from?

The clip at the top of this page is from All the President's Men (1976).

to be careful of sth; to make an effort to be aware of what is happening, so that you will notice if anything bad or unusual happens

Oxford90% of films
to be careful of sth
Oxford10% of films
to make an effort to be aware of what is happening, so that you will notice if anything bad or unusual happens

Definitions from the Oxford Advanced Learner's Dictionary, 9th edition

You know, my girlfriend told me to watch out for you.

Said in 8 films · #1