What does contradictiō in adjectō mean in Latin?

contradictiō in adjectō, a noun, means “contradiction in terms, oxymoron, self-contradiction”.

What is the genitive of contradictiō in adjectō?

The genitive singular is contradictiōnis in adjectō. contradictiō in adjectō is third declension.

nounthird declension

contradictiō in adjectō f (genitive contradictiōnis in adjectō)

Medieval LatinNew Latincontradiction in terms, oxymoron, self-contradiction
Nam Homo mortuus, includit in se non viuum; Homo autem includit in se viuum: & ita sequitur contradictio in adiecto.For “dead man” encompasses not-living; “man”, however, encompasses living, and there thus follows a self-contradiction.1243 – 1316, Giles of Rome, In libros Aristotelis primum et secundum Perhiermenias; republished as In Porphyrij Isagogen, Aristotelis Categorias, et lib. Peri Hermenias […] absolutissima Commentaria, 1591, page 181:
Nam qui est stultus, quomodo ille potest dici ingeniosus & ad studia literarum aptus? Videtur enim esse contradictio in adjecto.For if someone is stupid, how can he be said to be ingenious and gifted in the study of letters? There seems, therefore, to be a self-contradiction.1656, Christian Matthiae, Theatrum historicum theoretico-practicum, in quo quatuor monarchiae […] , page 489:

Literally, “contradiction in what is qualified”, i.e., originally, a contradiction between a noun and a qualifying adjective.