Lexical Definition

‎ἀκέραιος‎ akéraios (ak-er'-ah-yos) innocent ^G:A
from ‎Α‎ (as a negative particle) and a presumed derivative of ‎κεράννυμι‎

harmless, simple.

• unmixed, i.e. (figuratively) innocent

Abbott-Smith

** ἀκέραιος, -ον (< κεράννυμι), [in LXX: Es 8:13*;]
unmixed, pure, hence, metaph. (cf. MM, VGT, s.v.), guileless, simple: Mt 10:16, Ro 16:19, Phl 2:15.†
SYN.: ἄδολος, ἄκακος, ἁπλοῦς (cf. Ellic. on Phl 2:15; Tr., Syn., §lvi).

Abbott-Smith References

Liddell-Scott-Jones

ἀκέραιος-ος, ον

(feminine -αία [Refs 5th c.BC+], pure, unmixed, ὕδωρ[Refs 4th c.BC+]; untouched, γῆ, νομή, [Refs 5th c.BC+]; unalloyed, ἡδοναί[Refs 4th c.BC+]

__2 of persons, pure in blood, [Refs 5th c.BC+]
__II unharmed, unravaged, ἀ. ἀπολαμβάνειν τὴν πόλιν[Refs 5th c.BC+]; δύναμις, of an army, in full force, [Refs 5th c.BC+]; of troops, fresh, [Refs 5th c.BC+]; of property, untouched, οὐσία[Refs 4th c.BC+]; ἐᾶν τι ἀσινὲς καὶ ἀ. [Refs]; of a person, Persae.[Refs]
__II.2 metaphorically, pure, inviolate, ἀκέραιοςον ὡς σῴσαιμι Μενέλεῳ λέχος[Refs 5th c.BC+]; [τέχνη] ἀβλαβὴς καὶ ἀ. [Refs 5th c.BC+]; complete, perfect, φαντασίαι[Refs 2nd c.BC+]
__II.3 of persons, uncontaminated, guileless, [Refs 5th c.BC+]; incorruptible, κριτής[Refs 5th c.BC+]; unprejudiced, with an open mind, [Refs 2nd c.BC+]
__II.4 ἐξ ἀκεραίου anew, [Refs]; while matters are undecided, [Refs]; ἀκέραιοςον ἐᾶν leave alone, [Refs]; εἰς -ον ἀποκαθιστάναι, = Latin in integrum restituere, [Refs]adverb -ως, of payment, in full, [Refs 1st c.BC+]; unreservedly, [Refs 1st c.BC+]