oppositio
From LSJ
ἐπ' αὐτὸν ἥκεις τὸν βατῆρα τῆς θύρας → you've come to the crux of the matter, come to the point, hit the nail on the head, you've come to the very threshold of the door, you are come to the very threshold of the door, you've arrived at the truth of the matter
Latin > English (Lewis & Short)
oppŏsĭtĭo: (obp-), ōnis, f. oppono,
I an opposing, opposition (class.): disparatum est id, quod ab aliquā re per oppositionem negationis separatur, hoc modo: sapere, et non sapere, Cic. Inv. 1, 28, 42; Gell. 6, 1, 4: scientiae, Vulg. 1 Tim. 6, 20.
