The headword phrase is presumably quoted from somewhere. (Hesychius uses it in the accusative case when glossing the word εὔδιον .)
The adjective σκεπεινός is a variant of σκεπανός (from σκέπη : sigma 560, cf. sigma 558). It is used substantively in the dative plural at 2 Ezra 14.7 LXX (Nehemiah 4.7), meaning "sheltered places." The spelling σκεπινός also occurs in later Greek.