In his Institutes of oratory: or, Education of an orator. In twelve books Quintilian argues that a definition can be overthrown in two ways. As an example, his uses the definition of a horse as a rational or irrational animal. The English translator make the note that, at this very point, something must have been “dropped out of the text here, probably through the negligence of the transcribers”. He offers to complete the missing part following the recommendations of another English translator. So here the two ways by which a definition can be overthrown, and an illustration of both cases. The part that is made up by the translators is in blue :

(…) and a definition is overthrown in two ways, by being proved to be false or incomplete. It may indeed have a third fault, that of having no relation to the matter under consideration, but it will hardly be made faulty in this respect, except by fools. We make a false definition, if we say, A horse is a rational animal; for a horse is indeed an animal, but irrational. It is an incomplete one, if you say, A horse is an irrational animal; for to be irrational is common to a horse with other beasts; and that which is common to anything else will not be peculiar to the thing defined.”

– QUINTILIAN, Institutes of oratory: or, Education of an orator. In twelve books, Book VII, Chap. II, §23-34 (tr. by John Selby Watson, Henry G. Bohn, 1856, p. 38 – Goolge Books)
The last part of this argument is used by Roberto Esposito in his essay Communitas to stress the fact that “In all neo-Latin Languages (though not only) common is what is not proper, that begins where what is proper ends” – ESPOSITO, Roberto ([1998]2010). Communitas, tr. Thimothy Campbell, Stanford: Stanford University Press, p. 3