be on the lookout for
US /bi ɑn ðə ˈlʊkˌaʊt fɔr/
UK /bi ɑn ðə ˈlʊkˌaʊt fɔr/
1.
to be actively watching or searching for something or someone
:
•
We need to be on the lookout for any suspicious activity.
•
The police are on the lookout for the escaped prisoner.