to beware;  to mind;  to take care not to do something;  to be careful;  to take precautions;  to watch for something;  to be on the alert against/for something
The director asked the salesmen to watch out for forged bank-notes
Be on the watch for pickpockets!;  Beware of pickpockets!;  Look out for pickpockets!
Police will look out for rioters;  Police will take precautions against rioters
in anticipation of something;   (just) in case;  lest;  for fear that;  for fear of doing something
To take plenty of warm clothes in anticipation of bad weather/ (just) in case the weather is bad
Prison-breakers tried to tiptoe for fear that/lest the guard might discover them;  Prison-breakers tried to tiptoe for fear of being discovered by the guard