It is a determination that something should be rejected, when it really should have been accepted.
Similarly, a false positive is something that was accepted, when it should have been rejected.
If you have a sufficiently high candidate pool. you can (for a while, at least) live with an interview process with a relatively high false negative rate (that is, x% of the time you don't hire people you should have).
If it is typically quick to go from "in through the door" to "is a productive member of the team", it may be that you can live with a high false positive rate (that is, y% of the time you hire people you shouldn't have).
Similarly, a false positive is something that was accepted, when it should have been rejected.
If you have a sufficiently high candidate pool. you can (for a while, at least) live with an interview process with a relatively high false negative rate (that is, x% of the time you don't hire people you should have).
If it is typically quick to go from "in through the door" to "is a productive member of the team", it may be that you can live with a high false positive rate (that is, y% of the time you hire people you shouldn't have).