Abbott-Smith Manual Greek Lexicon
ἀ-σύν-θετος (G802)
1 ἀ-σύν-θετος , -ον ( συντίθεμαι ; v. M, Pr. , 222; MM, s.v.), [in LXX: Je 3:7 , 8 , 10 , 11 ( בּגד )*;] false to engagements , not keeping covenant , faithless (MM, s.v.): Ro 1:31 .†
G. Abbott-Smith, A Manual Greek Lexicon of the New Testament (1922) — public domain