If you are keeping a lookout
for something or are on the lookout
for it, you are alert
about it, either because you do not want
it or because it will be unpleasant or harmful
and you need to avoid
Keep a lookout for a nasty little organization calling itself Defence Through Strength.
Nature lovers will be on the lookout for eagles, cormorants, and the occasional whale.
COBUILD Advanced English Dictionary. Copyright © HarperCollins Publishers