Abbott-Smith Manual Greek Lexicon
πρόθυμος (G4289)
3 πρόθυμος , -ον , [in LXX: I Ch 28:21 , II Ch 29:31 ( נָדִיב ), Hb 1:8 ( חוּשׁ ), al.;] willing , ready : Mt 26:41 , Mk 14:38 ; neut., τὸ π. = ἡ προθυμία (Thuc., al., III Mac 5:26 ), οὕτως τὸ κατ’ ἐμὲ (= cl. τὸ ἐμὸν ) π. , Ro 1:15 (but v. ICC , in l.).†
G. Abbott-Smith, A Manual Greek Lexicon of the New Testament (1922) — public domain