ἑκούσιον

From LSJ

ἡγούμενος τῶν ἡδονῶν ἀλλ' οὐκ ἀγόμενος ὑπ' αὐτῶν → of his pleasures he was the master and not their servant

Source

English (Strong)

neuter of a derivative from ἑκών; voluntariness: willingly.

Russian (Dvoretsky)

ἑκούσιον: τό свободная воля Plat., Arst.