John Gill Commentary Deuteronomy 19:16

"If an unrighteous witness rise up against any man to testify against him of wrong-doing," — Deuteronomy 19:16 (ASV)

If a false witness rise up against any man
In a court of judicature:

to testify against him :
that which is not true of him, let it be in what case it will; Aben Ezra instances in idolatry, but it holds good of any other.