κλᾷσθρον

From LSJ

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

Source

Greek (Liddell-Scott)

κλᾷσθρον: «κλεῖθρον»· Ἡσύχ.