Quick Definition
I ignore, despise
Strong's Definition
to make utterly nothing of, i.e. despise
Derivation: from G1537 (ἐκ) and a derivative of the neuter of G3762 (οὐδείς);
KJV Usage: set at nought
Thayer's Greek Lexicon
ἐξουδενέω, ἐξουδένω: 1 aorist passive subjunctive 3 person singular ἐξουδενηθῇ; perfect passive participle ἐξουδενημενος; to hold and treat s as of no account, utterly to despise: τόν λόγον, passive, 2Co_10:10 Lachmann to set at nought, treat with contumely: a person, passive, Mar_9:12 L Tr WH (Eze_21:10). Cf. Lob. ad Phryn., p. 182; (Buttmann, 28 (25); Winers Grammar, 91 (87); Sophocles Lexicon, under the word; WH's Appendix, p. 166).
STRONGS NT 1847: ἐξουδενόωἐξουδενόω, ἐξουδένω: (1 aorist passive subjunctive 3 person singular ἐξουδενώθη); equivalent to ἐξουδενέω, which see: Mar_9:12 R G; often in the Sept., especially for αΘΜζΘδ and ξΘΰΗρ. (Cf. references in the preceding word.)
STRONGS NT 1847: ἐξουθενόωἐξουθενόω, equivalent to ἐξουθενέω, which see: Mar_9:12 Tdf.
Mounce Concise Greek Dictionary
ἐξουδενέω exoudeneō 1x
also spelled ἐξουδενόω , to treat with contempt, Mar_9:12
Abbott-Smith Greek Lexicon
† ἐξ -ουδενέω
( Rec. -όω ; T , -θανόω ), -ῶ ,
[in LXX (with vv. ll . -όω , -θενέω , -θενόω ) for H936 , H959 , H3988 , H947 , etc.;]
to despise, set at nought: Mar_9:12 ( cf. ἐξουθενέω ).†
Liddell-Scott — Intermediate Greek Lexicon
ἐξουδενόω fut. ώσω [Etym: οὐδείς] "to set at naught", NTest.
STEPBible — Tyndale Abridged Greek Lexicon
ἐξ-ουδενέω
(Rec. -όω; T, -θανόω), -ῶ, [in LXX (with vv. ll. -όω, -θενέω, -θενόω) for בּוּז, בָּזָה, מָאַס, בּוּס, etc. ;]
to despise, set at nought: Mrk.9:12 (cf. ἐξουθενέω).†
(AS)