From in (“in”) + cassum (“hollow, empty”), accusative of cassus.
in cassum (not comparable)
- in vain
c. 194 BCE
- Bene promittis multa ex multis: omnia in cassum cadunt.
- You promise many things to many people: they all prove to be in vain.
- You pile up fine promises sky-high: down they all drop to nothing. (translated by Paul Nixon, Plautus IV (Loeb), 1980, p. 37)