0 a secret warning or piece of secret information: --
1 a warning or information that something may happen: --
For example, one tip-off led to five people being arrested.
The police said that they had received a tip-off about the presence of explosives.
All these should be carried out before action is taken on an anonymous tip-off.
It is done only on a random basis and usually because there has been a tip-off.
I thought at the time that the immigration officers must have had some kind of advance information, some tip-off.
That will give the police the tip-off, and the immigrants will be liable to disappear or go to ground.
One of the other examples given is that the information is given on the basis of an anonymous tip-off.
The officer has a tip-off that there is known to be poaching in the district.
