What is "crassitia"

The gens Crassitia was a plebeian family at Rome. It is known chiefly from a single individual, Lucius Crassitius, a freedman and a Latin grammarian. He was a native of Tarentum, and originally named Pasicles, which he later changed to Pansa. He gave lectures on grammar, and taught the sons of many of the noblest families at Rome, including Iullus Antonius, the son of the triumvir Marcus Antonius. He earned renown for his commentary on Gaius Helvius Cinna's poem, Smyrna, and his praises were celebrated in an epigram of Suetonius. In later life he gave up teaching in order to devote himself to philosophy.

Cicero mentions a Crassitius amongst the friends of Marcus Antonius. He may have been the former master of Pasicles, afterwards Lucius Crassitius, or they may have been the same man.