俱舍論疏 5.31

5.31

論「無想者定至名無想定」，此釋名也。前是屬主，後是持業。無想假者，有此定故名無想定，屬主釋也。即定無想名無想定，持業釋也。

On the text of the Treatise, "The attainment of non-conception... is called the non-conception attainment": This explains the compound name. The former is a genitive compound (ṣaṣṭhī-tatpuruṣa), the latter is an appositional compound (karmadhāraya). It is the non-conception attainment because the nominal agent of non-conception possesses this attainment: this is the genitive interpretation. That the attainment itself is non-conception and thus called the non-conception attainment: this is the appositional interpretation.