Lexical Definition

‎ἐπίνοια‎ epínoia (ep-in'-oy-ah) thought ^G:N-F
from ‎ἐπί‎ and ‎νοῦς‎

thought.

• attention of the mind, i.e. (by implication) purpose

Abbott-Smith

ἐπίνοια, -ας, ἡ (< ἐπινοέω, to contrive) [in LXX: Je 20:10, Wi 6:16 9:14 14:12 15:4, Si 40:2, II Mac 12:45, IV Mac 17:2 * ;]
a thought, design: Ac 8:22.†

Abbott-Smith References

Liddell-Scott-Jones

ἐπίνοια, ἡ,

thinking on or of a thing, thought, notion, οὐδ᾽ ἐς ἐπίνοιαν ἰέναι τινός [ἐπίνοιαν ποιήσασθαί τινος 2nd c.BC: Polybius Historicus 1.20.12; τὰς ἐ. εἴς τι φέρειν 1st c.BC: Dionysius Halicarnassensis “Epistula ad Pompeium” 1 ">Refs 5th c.BC+]; πάσαις ταῖς ἐ. γίγνεσθαι περί τι 2nd c.BC: Polybius Historicus 5.110.10; conception, idea, ἐναργὴς τοῦ πράγματος ἐ. [Refs]; κατ᾽ ἐπίνοιαν in idea, opposed to κατὰ περίπτωσιν (which see), [Refs 1st c.AD+]

__2. power of thought, inventiveness, οἶνον σὺ τολμᾶς εἰς ἐ. λοιδορεῖ; [Refs 4th c.BC+]
__3. invention, device, conceit, ἐ. ἀστειοτάται [Refs]; θαυμαστὰς ἐξευρίσκων ἐ. [ἐπίνοιαι 4th c.BC: Aristoteles Philosophus “de Mundo” 399b17; πενία ἐπινοιῶν διδάσκαλος 2nd c.AD: Secundus Gnomologus “Sententiae - FPG” 10. ">Refs 4th c.BC+]
__4. purpose, design, τίν᾽ ἐ. ἔσχεθε; [Refs 5th c.BC+]; τίς ἐ.; [Refs]; κατὰ τὴν ἐκφορὰν καὶ τὴν ἐ. [Refs]., = sua sponte, [Refs 4th c.AD+]
__II. afterthought, second thoughts, ψεύδει γὰρ ἡ 'πίνοια τὴν γνώμην 5th c.BC: Sophocles Tragicus “Antigone” 389.
__III. intelligence, κοινὴ ἐ. [Refs]
__III.2. Psychol., reflection on experience, retrospection, [Refs]