Definition "Alessandria" in Collins English Dictionary & Thesaurus

alert (alerts plural & 3rd person present) (alerting present participle) (alerted past tense & past participle )

1  adj If you are alert, you are paying full attention to things around you and are able to deal with anything that might happen. (=attentive)
We all have to stay alert..., He had been spotted by an alert neighbour.
♦ alertness    n-uncount
The drug improved mental alertness.

2 adj If you are alert to something, you are fully aware of it.
v-link ADJ to n
The bank is alert to the danger.

3 n-count An alert is a situation in which people prepare themselves for something dangerous that might happen soon.
Due to a security alert, this train will not be stopping at Oxford Circus.

4  verb If you alert someone to a situation, especially a dangerous or unpleasant situation, you tell them about it.
He wanted to alert people to the activities of the group...  V n to n
I was hoping he'd alert the police.  V n

5
→ red alert

6 If soldiers or police are on alert, they are ready to deal with anything that may happen.
♦ on alert phrase PHR after v, v-link PHR
Soldiers and police have been put on alert.

7 If you are on the alert for something, you are ready to deal with it if it happens.
♦ on the alert phrase PHR after v, v-link PHR
They want to be on the alert for similar buying opportunities.