δυσέκπλυντος

From LSJ

ἰχθύς ἐκ τῆς κεφαλῆς ὄζειν ἄρχεται → the fish stinks from the head, a fish rots from the head down, the fish rots from the head down, fish begin to stink at the head, the fish stinks first at the head, corruption starts at the top, the rot starts at the top

Source

German (Pape)

[Seite 678] oder besser δυσέκπλυτος, schwer auszuwaschen, Plut. frat. am. 17 u. a. Sp.

Spanish (DGE)

-ον
difícil de purgar ὕλη ref. los humores de una herida, Alex.Aphr.Pr.4.36.