What does chronographus mean in Latin?

chronographus, a noun, means “chronographer, annalist, chronicler”.

What is the genitive of chronographus?

The genitive singular is chronographī. chronographus is masculine, second declension.

noun · masculinesecond declension

chronographus m (genitive chronographī)

chrŏnŏgrăphus, i, m., = χρονογράφος,

I. a chronographer, annalist, Sid. Ep. 8, 6 fin.

Borrowed from Ancient Greek χρονογράφος (khronográphos).