This was the name of 3 biblical men.
Justus, a longtime disciple of Christ who was an eye-witness of His resurrection
He was also known by the name Joseph Barsabas.
He and Matthias are mentioned only in Acts 1:23.
“They must have been among the earliest disciples of Jesus, and must have been faithful to the end; they must have been well known and esteemed among the brethren. What became of them afterwards, and what work they did, are entirely unknown” (Lindsay's Acts of the Apostles).
Justus, a Jewish Christian (proselyte) at Corinth
It was in his house, next door to the synagogue, that Paul held meetings and preached after he left the synagogue (Acts 18:7).
Justus, a Jewish Christian, also called Jesus
He was Paul’s only fellow-laborer in Rome, where he wrote his Epistle to the Colossians (Col. 4:11).