watch out Idiom, Proverb
watch out
be careful, look out Watch out! There's a truck!
watch out for
watch and care for, keep an eye on Jamie, you watch out for Cathy. Hold her hand at the crosswalk.
look out|look|watch|watch out
v. 1. To take care; be careful; be on guard.

Usually used as a command or warning.
"Look out!" John called, as the car came toward me. "Look out for the train," the sign at the railroad crossing warns. 2. To be alert or watchful; keep watching.
A collector of antique cars asked Frank to look out for a 1906 gas head lamp. Compare: EYE OUT, ON THE WATCH. 3.
informal To watch or keep (a person or thing) and do what is needed; provide protection and care.

Used with "for".
Lillian looked out for her sister's children one afternoon a week. Uncle Fred looked out for his brother's orphan son until the boy was through college. Compare: LOOK AFTER.
watch out
To pay absorption (usually because crisis is imminent). Often acclimated as an imperative. You charge to watch out for all these cords—they're a austere benumbed hazard. Watch out! There's a car coming!Learn more: out, watchwatch out
v.
1. To be accurate or on the alert; booty care: If you don't watch out, you'll abatement on the ice.
2. watch out for To be accurate of some danger: Watch out for falling rocks!
Learn more: out, watch