When it is a full-grown pig. Specifically we have to do with the word δελφάκιον, defined by LSJ as a ‘sucking pig’. Now, it is true that the word itself is a diminutive of δέλφαξ, and that a δέλφαξ is a fullgrown pig; but not every diminutive indicates something small or immature. A diminutive may be disparaging (‘kinglet’), friendly (‘Joey’), pleonastic (‘Katyushka’), ironic (Robin Hood's Little John), or simply a regular part of a word (‘Mädchen’) or a name (Theodor Herzl). A diminutive may refer to a difference of importance (‘baronet’) or sex (‘majorette’) rather than size, and may even refer to something larger that of the simple form: it is by a quirk of historical linguistics that a hamlet is larger than a home, but it is a fact of the synchronic language. The -ιον ending in and of itself cannot establish that a δελφάκιον is immature.