Lexical Definition

‎ῥώννυμι‎ rhṓnnymi (hrone'-noo-mee) farewell G:V
prolongation from (to dart

farewell.

Usage: 2 forms in 2 verses
Form Translated As     In Verse(s)
ἔρρωσο Farewell Acts.23.30
ἔρρωσθε Farewell Acts.15.29

Abbott-Smith

ῥώννυμι [in LXX: II Mac 9:20 11:21, 28, 33; III Mac6 * ;]
to strengthen; most freq. in pf., ἔρρωμαι, to put forth strength, be strong, hence, often in imperat., ἔρρωσο, ἔρρωσθε, farewell (Lat. vale): Ac 15:29 23:30 Rec., R, mg.†

Abbott-Smith References

Book Refs
Acts 15:29 · 23:30

Liddell-Scott-Jones

ῥώννυμι,

[Refs 5th c.BC+]; ῥωννύω, [Refs 5th c.BC+]future ῥώσω (ἐπιρ-) [Refs 1st c.AD+]: aorist ἔρρωσα [Refs 5th c.BC+]:—passive, ῥώννῠμαι [Refs 1st c.AD+]: future ῥωσθήσομαι [Refs 2nd c.AD+]: aorist ἐρρώσθην [Refs 5th c.BC+]perfect ἔρρωμαι (see. below):—strengthen, τροφὴ ῥώννυσι [Refs 5th c.BC+]; . τὰν ψυχὰν ποτ᾽ (πρὸς) ἀλκάν [Refs 5th c.BC+]

__II mostly in perfect passive (with present sense) ἔρρωμαι, and pluperfect ἐρρώμην (as imperfect):—have strength or might, γέροντές ἐσμεν κοὐδαμῶς ἐρρώμεθα [Refs 5th c.BC+]
__II.2 to be eager, enthusiastic, glossed by προθυμεῖσθαι, [Refs 5th c.BC+]: with infinitive, to be eager to do, ἔρρωτο πᾶς ξυνεπιλαμβάνειν [Refs 5th c.BC+]
__II.3 to be in good health, [Refs 5th c.BC+], farewell, the usual way of ending a letter, as in [Refs 5th c.BC+], and at the close of [Refs 5th c.BC+]; εἰ ἔρρωσθε εὖ ἂν ἔχοι [Refs 2nd c.BC+]
__II.4 frequently in participle ἐρρωμένος (which see).