Lexical Definition

‎εἰλικρινής‎ eilikrinḗs (i-lik-ree-nace') pure ^G:A
from (the sun's ray) and ‎κρίνω‎

pure, sincere.

• judged by sunlight, i.e. tested as genuine (figuratively)

Abbott-Smith

** εἰλικρινής, -ές, [in LXX: Wi 7:25 אB * ;]
unalloyed, pure (Lat. sincerus; v. DCG, ii, 635a);
(a) of unmixed substances;
(b) of abstract ideas;
(c) of ethical purity: Phl 1:10, II Pe 3:1.†
SYN.: ἁγνός (q.v.), καθαρός, cf. Tr., Syn.: §lxxxv; DB, iv, 176a; Cremer, 378; Westc. on I Jo 3:3.

Abbott-Smith References

Liddell-Scott-Jones

εἰλικρινής-ής, ές,

unmixed, without alloy, pure, ἐκ πυρὸς τοῦ -εστάτου καὶ ὕδατος [Refs 5th c.BC+]; θέρμη, ψῦξις, [Refs]; διὰ τὸ εἰλικρινήςῆ ἕκαστα εἶναι (i.e. τὰ φῦλα) distinct and separate, [Refs 5th c.BC+]; τὸ ἧττον εἰ., opposed to τὸ καθαρώτερον, [εἰλικρινήςοῦς [prev. author] “HA” 627a3; εἰ. καὶ ἀμιγής [prev. author] “de An.” 426b4; ἐν μεγάλῳ εἰ. καὶ κενῷ 4th-3rd c.BC: Epicurus Philosophus “Epistulae” 2p.37U. (perhaps καὶ εἰ.); τὸ ἓν εἰ. καὶ καθαρόν 1st-2nd c.AD: Plutarchus Biographus et Philosophus 2.393c. ">Refs 4th c.BC+]

__2 pure, simple, absolute, αὐτῇ καθ᾽ αὑτὴν εἰλικρινήςεῖ τῇ διανοίᾳ χρώμενος the pure and absolute intellect, [Refs 5th c.BC+]; γνωσόμεθα.. πᾶν τὸ εἰ. the pure and absolute, [Refs]; τὸ καθαρόν τε καὶ εἰ. [Refs 5th c.BC+]; ἡδονὴ εἰ. [Refs 4th c.BC+]; also of evil things, sheer, absolute, ἀδικία [Refs 5th c.BC+]
__3 sincere, ἀπόδεξις [Refs 3rd c.BC+]; of persons, [NT]. adverb - νῶς [Refs 1st c.BC+]
__4 total, ἐκλείψεις [Refs 2nd c.AD+]
__II adverb -νῶς without mixture, of itself, simply, absolutely, διὰ τὸ εἰ. εἶναι Ἕλληνας καὶ ἀμιγεῖς βαρβάρων [Refs 5th c.BC+]; τὸ εἰ. ὄν absolute being, [Refs 4th c.BC+]; without qualification, - νῶς Ταραντῖνοι [Refs 2nd c.AD+]: Ionic dialect εἰλικρινής-έως, κρίνεσθαι to have a clear crisis, [Refs 5th c.BC+] —The word is confined to Prose.

_{LSJ Scripture Refs: Phil.1.10}