Quick Definition
I utterly refute
Strong's Definition
to prove downright, i.e. confute
Derivation: middle voice from G1223 (διά) and a compound of G2596 (κατά) and G1651 (ἐλέγχω);
KJV Usage: convince
Thayer's Greek Lexicon
διακατελέγχομαι: imperfect διακατηλεγχομην; to confute with rivalry and effort or in a contest (on this use of the preposition διά in compos. cf. Herm. ad Vig., p. 854; (others give it here the sense of completeness; see διά, C. 2)): with the dative of person (Winers Grammar, § 31, 1 f.; Buttmann, 177 (154)); not found except in Act_18:28 (R. V. powerfully confuted).
Mounce Concise Greek Dictionary
διακατελέγχομαι diakatelenchomai 1x
to maintain discussion strenuously and thoroughly, to totally refute, Act_18:28
Abbott-Smith Greek Lexicon
*† δια -κατ -ελέγχομαι ,
to confute completely: Act_18:28 .†
Liddell-Scott — Intermediate Greek Lexicon
διακατελέγχομαι fut. ξομαι Mid. "to confute thoroughly", τινι NTest.
STEPBible — Tyndale Abridged Greek Lexicon
δια-κατ-ελέγχομαι
to confute completely: Act.18:28.†
(AS)