γεῖσσον

From LSJ

πάτερ, ἄφες αὐτοῖς, οὐ γὰρ οἴδασιν τί ποιοῦσιν → father, forgive them, for they know not what they do

Source

French (Bailly abrégé)

v. γεῖσον.

German (Pape)

γεῖσον.