ὀγδοαῖος
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)
α, ον,
A on the eighth day, Plb.5.52.3, al., Plu.2.288c, Gal.9.869, etc. II of fever, recurring on the eighth day, octavan, Id.7.505.