Usage: 2 forms in 2 verses
Form Translated As     In Verse(s)
συγγενώμεθα we may be intimate LXX.Gen.19.5
συγγενέσθαι to be intimate LXX.Gen.39.10

Liddell-Scott-Jones

συγγίνομαι (sunginomai) be intimate with G:V

συγγίνομαι,

Ionic dialect and later Gr. συγγίν- []: future -γενήσομαι, aorist -εγενόμην, perfect -γέγονα (also συγγεγένημαι [Refs 5th c.BC+]:—to be born with, ἅμα σ. γινομένοις [Refs 4th c.BC+]

__II associate, keep company with, hold converse with, τινι [Refs 5th c.BC+]; πᾶσαν τὴν συνουσίαν σ. [Refs 5th c.BC+]: absolutely, coexist, cohere, ἀήθεα [Refs 5th c.BC+]
__II.2 of disciples or pupils, hold converse with a master, consult him, περί τινος, τίνος πέρ; [Refs 5th c.BC+]; of the master, [Refs 1st c.AD+]
__II.3 σ. γυναικί have sexual intercourse with her, [Refs 5th c.BC+]; of the woman, [Refs 5th c.BC+]
__II.4 come to assist, τινι [Refs 5th c.BC+]; ξὺν δὲ γενοῦ πρὸς ἐχθρούς [Refs 4th c.BC+]
__II.5 absolutely, come together, meet, [Refs 5th c.BC+]; οἱ συγγιγνόμενοι comrades, [Refs 5th c.BC+]; ἀριθμὸς συγγ. coming to our aid, [Refs 5th c.BC+]
__III become acquainted or conversant with, σπλάγχνοισι [Refs 5th c.BC+]