καπνέλαιον
From LSJ
κρεῖττον σιωπᾶν ἐστιν ἢ λαλεῖν μάτην → it's better to keep silence than to speak without reason (Menander)
English (LSJ)
τό, A oily resin from trees, Gal.13.626, Alex.Trall.3.2. II = καπνιστὸν ἔλαιον, Edict.Diocl.Delph.
German (Pape)
[Seite 1323] τό, Rauchöl, ein von selbst ausfließendes Harz, Galen.