λεύκανσις
From LSJ
ὃν οὐ τύπτει λόγος οὐδὲ ῥάβδος → if words don't get through, neither a beating will | if the carrot doesn't work, the stick will not work either | whom words do not strike, neither does the rod
English (LSJ)
εως, ἡ, a growing white, Arist.Ph.224b15, Alex.Aphr.in Top.304.1; clarification of oil, Gal. 11.484.
German (Pape)
[Seite 33] ἡ, das Weißmachen, Arist. phys. 5, 6.
Greek (Liddell-Scott)
λεύκανσις: ἡ, τὸ λευκαίνειν ἢ λευκαίνεσθαι, Ἀριστ. Φυσ. 5. 1, 5, κτλ.
Russian (Dvoretsky)
λεύκανσις: εως ἡ побеление Arst.