Same or (see below) similar entry in other lexica. The headword is either masculine/feminine accusative singular or neuter nominative/accusative singular of this rare adjective.
The glossing here and in most other lexica understands the word literally, but Hesychius delta2561 also has the gloss dusermh/neuton "hard to interpret", and this (cf. LSJ s.v.) would fit with both of the instances extant outside lexicography: Porphyry, Life of Pythagoras 48; Cyril of Alexandria, Against Julian 1.25.