🔼The name Tertullus in the Bible
There is only one man named Tertullus mentioned in the Bible. His services as a lawyer were acquired by the Jewish high priest Ananias in order to accuse Paul in the court of the Roman governor Felix (Acts 24:1 and 24:2).
Since we may expect that Ananias was an expert in Jewish law, Tertullus was surely a supposed expert in Roman law, who knew precisely which buttons to push, or so he thought. After some due puckering towards Felix, Tertullus started out by rattling off Paul's supposed violations of cardinal Roman edicts: he's promoting a sect that refuses partaking in the imperial cult (punishable by death), and he's desecrating local temples, which was against Rome's cardinal rule of religious tolerance, i.e. the still very modern promotion of a religious milkshake designed to corrode any respect for absolute truth.
Paul, a towering intellect and thoroughly educated in a wide spectrum of topics and cultures, realized quickly that Tertullus was nothing but a bluffing amateur, and began his defense with fitting cheer (Acts 24:10). Felix, knowing about The Way (which was, together with Nazarenism, probably one of the source-sects of early Christianity associated with John the Baptist, see Matthew 3:3 and Isaiah 40:3) became frightened by Paul's words, hoped he would try to bribe himself out (Acts 24:22, 24:26) and decided the favor of the Jewish elite was more preferable than the favor of YHWH, and kept Paul in jail (Acts 24:27).
🔼Etymology and meaning of the name Tertullus
The name Tertullus is a diminutive form of the name Tertius, which is a common adjective meaning Third, and names derived from numbers were very common in Roman times; just think of Octavian, meaning Eighth, who changed his name to Augustus upon becoming Rome's first emperor.
The English language has no real facility to convey diminution so translating this name literally into English is difficult. But then as well as now, a diminutive doesn't exactly evoke reverence; Tertullus is a name along the line of John Boy or Lil' Kim or Billy-Bob Junior.
The author of Acts obviously doesn't shy away from humor, and the character of Tertullus is clearly portrayed as an ignorant belter with little effect one way or the other.