Lexical Definition

‎ἄδικος‎ ádikos (ad'-ee-kos) unjust ^G:A
from ‎Α‎ (as a negative particle) and ‎δίκη‎

unjust, unrighteous.

• unjust
• by extension wicked
• by implication, treacherous
• specially, heathen

Abbott-Smith

ἄδικος, -ον (< δίκη), [in LXX for שׁקר, עול, etc.;]

1. unjust: Ro 3:5, He 6:10.
2. unrighteous, wicked: Lk 16:11 18:11, Ac 24:15, I Co 6:1, 9 I Pe 3:18; opp. to δίκαιος, Mt 5:45; to εὐσεβής, II Pe 2:9; to πιστός, Lk 16:10 (Cremer, 200).†

Abbott-Smith References

Liddell-Scott-Jones

ἄδικος, ον,

(δίκη) of persons, wrongdoing, unrighteous, unjust: ἄνθρωποι[Refs 8th c.BC+]: superlative -ώτατος[Refs 5th c.BC+] unjust in a thing, ἔς τινα towards a person, [Refs 5th c.BC+]; ἄ. [ἐν τῷ ἀστραγαλίζειν] one who plays unfairly, [Refs 5th c.BC+]: with infinitive, so unjust as to. NT.Heb.6.10.

__2 ἄ. ἵπποι obstinate, unmanageable, [Refs 5th c.BC+]; ἄ. γνάθος the hard mouth of a horse, [Refs]
__II of things, unjust, unrighteous, ἔργα[Refs 8th c.BC+]; ἄ. λόγος frequently in [Refs 5th c.BC+]; ἄρχειν χειρῶν ἀ. begin an assault, [Refs 5th c.BC+]; τὸ δίκαιον καὶ τὸ ἄ., τὰ δίκαια καὶ τὰ ἄ. right and wrong, [Refs 5th c.BC+]; πλοῦτος ἄ. ill-gotten, unrighteous, [LXX+5th c.BC+]; ἡ ἄ... συναγωγὴ ἀνδρὸς καὶ γυναικός the unrighteous union, [Refs 5th c.BC+]; ἄ. δίκη vexatious suit, [Refs 5th c.BC+]
__II.2 of the punishment of wrongdoing, Ζεὺς νέμων ἄδικα κακοῖς[Refs 5th c.BC+]
__III ἄ. ἡμέρα, i.e. ἄνευ δικῶν, a day on which the courts were shut, [Refs 2nd c.AD+] who has not appeared in court, [Refs 5th c.BC+]
__IV adverb -κως[Refs 6th c.BC+]; εἴτε ὦν δὴ δικαίως εἴτε ἀ. jure an injuria, [Refs 5th c.BC+]; οὐκ ἀ. not without reason, [Refs 5th c.BC+]

_{LSJ Scripture Refs: Heb.6.10 ☩ LXX.Amos.8.5}