What does āvertārius mean in Latin?

āvertārius, a noun, means “packhorse”.

What is the genitive of āvertārius?

The genitive singular is āvertāriī. āvertārius is masculine, second declension.

noun · masculinesecond declension

āvertārius m (genitive āvertāriī or āvertārī)

āvertārĭus, ii, m. averta (sc. equus),

I. a horse that bears the averta, Cod. Th. 8, 5, 22, § 1.

From āverta.