ἑκούσιος, ἑκούσιον (ἑκών), voluntary: κατά ἑκούσιον, of free will, Phm_1:14. (Num_15:3; καθ' ἑκουσιαν, Thucydides 8, 27 ("The word understood in the one case appears to be τρόπον (Porphyry, de abst. 1, 9 καθ' ἑκούσιον τρόπον, comp. Euripides, Med. 751 ἑκουσίῳ τρόπῳ); in the other, γνώμην so ἑκούσια (doubtful, see Liddell and Scott), ἐξ ἑκουσιας, etc.;" cf. Lobeck, Phryn., p. 4; Lightfoot on Philemon, the passage cited; cf. Winer's Grammar, 463 (432)).)

ἑκούσιος hekousios 1x voluntary, spontaneous, Phm_1:14

ἐκούσιος , -ον ( < έκών ), [in LXX chiefly for H5071 , as Num_15:3 (κατ᾿ ἑ );] usually of actions, voluntary: κατὰ ἑ ., of free will ( Lft ., in l ), Phm_1:14 .†

ἑκούσιος (~ ἑκούσιον ) [page 196] ἑκούσιος is found in what appears to be a legal formula in P Oxy X. 1280 .4 (iv/A.D.) ὁμολογῶ ἑκουσίᾳ καὶ αὐθαιρέτῳ γνώμῃ συντεθῖσθαί με πρὸς σέ , I acknowledge that I have of my own free will covenanted with you (Edd.) : cf. ib. XII. 1426 .14 (A.D. 332), and P Lips I. 26 .5 cited s.v. ἀμετανόητος . See also P Ryl II. 174 .23 (A.D. 112) ἑκ [ο ]ύσιον κατ [ο ]χήν , voluntary notification of a personal claim with reference to the repayment of a loan, and P Oxy III. 473 .3 (A.D. 138 160) the decree in honour of a gymnasiarch, who had devoted himself εἰς ἑκούσιον γυμν [ασ ]ιαρχίαν .

ἐκούσιος, -ον (έκών), [in LXX chiefly for נְדָבָה, as Num.15:3 (κατ᾽ ἑ) ;] usually of actions, voluntary: κατὰ ἑ., of free will (Lft., in l), Phm 14.† (AS)