Lexical Definition

‎συναίρω‎ synaírō (soon-ah'-ee-ro) to settle accounts ^G:V
from ‎σύν‎ and ‎αἴρω‎

reckon, take.

• to make up together, i.e. (figuratively) to compute (an account)

Abbott-Smith

συν-αίρω [in LXX: Ex 23:5 (עזב) * ;]
to take up together: σ. λόγον (of which there are several exx. in π.; v. Deiss., LAE, 118 f.; MM, i, xxiv; M, Pr., 160), to settle accounts, Mt 18:23, 24; seq. μετά, C. gen. pers., Mt 25:19.†

Abbott-Smith References

Liddell-Scott-Jones

συναίρω,

poetry συναείρω (which see):—middle aorist συνηράμην [Refs 5th c.BC+]; poetry aorist infinitive συνᾰρέσθαι probably conjecture in [Refs 2nd c.BC+]perfect infinitive written συνῆρσθαι, [Refs 1st c.AD+]:—take up together, [Refs 4th c.BC+]; σ. λόγον μετά τινος cast up accounts.., [NT+1st c.AD+]

__2 ={συνάγω}, gather in a harvest, τὰ γενήματα [Refs] — passive, ὁ ἐπὶ τοῖς βαλανείοις συναιρόμενος ῥύπος collected, [Refs 1st c.AD+]
__3 ὅπως συνάρωμεν διπλῆν εἰλαπίνην that we may celebrate together a double festival, [Refs 3rd c.AD+]
__4 τῷ Καίσαρι συναίρει espouses Caesar's cause, [Refs 2nd c.AD+]
__II middle, take part in a thing, with genitive of things, συνάρασθαι τοῦ πολέμου, τοῦ κινδύνου, [Refs 5th c.BC+]: with accusative of things, help in bearing or undertaking, ξυναίρεσθαι κίνδυνον [Refs 5th c.BC+]; also σ. Κύπριν engage in love with another, [Refs 5th c.BC+]; σ. τὴν Χάριν τινός espoused his cause, [Refs 2nd c.AD+]; συνάρασθαι εἰς τὸ αὐτό co-operate, [Refs 5th c.BC+]; σ. τινί with one, [Refs 1st c.AD+]; ἐπί τινα in attacking him, [Refs 1st c.AD+] help, assist, ταῖς ἀναγωγαῖς τοῦ πύου [Refs 2nd c.AD+]
__II.2 raise or use in helping, οὐ συναίρεται δόρυ [Refs 5th c.BC+]; πᾶν ὅ τι ἔχομεν σ. τῷ κάλλει enlist all we have in the service of beauty, [Refs 2nd c.AD+]
__II.3 τῶν σκελῶν σ. catch by both legs, trip up, [Refs 1st c.AD+]
__III middle [Refs 1st c.AD+]
__IV middle, annul jointly with another, ἐφ᾽ ᾧ συναρεῖταί μοι ἣν ἔχει ἡμῶν συνοικεσίου συγγραφήν [Refs 2nd c.BC+]:— passive, [Refs 2nd c.BC+]

_{LSJ Scripture Refs: Matt.18.23 ☩ Matt.18.24}