Meaning of "watch out for"

[Celik]

English Language Tests, Intermediate level

ESL/EFL Test #200 "Phrasal Verbs (T to W)", question 5

Rayleen ......... her little brother all the time.

(a) watched out for
(b) watched out about
(c) watched out

English Language Tests, Intermediate level

ESL/EFL Test #200 "Phrasal Verbs (T to W)", answer 5

Rayleen watched out for her little brother all the time.

Correct answer: (a) watched out for
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Please explain watch out for?

Celik

[Mister Micawber]

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Watch out for = supervise; monitor; take care of; protect; be on the alert on behalf of.
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Native English teacher at Mister Micawber's