Baby-sit and Look after

Baby-sit verb - Take watchful responsibility for.

Look after and baby-sit are semantically related In some cases you can use "Look after" instead a verb phrase "Baby-sit".

Look after verb - Keep under careful scrutiny.

Baby-sit and look after are semantically related in tend topic. You can use "Baby-sit" instead a verb "Look after", if it concerns topics such as care for, manage, protect.