Quick Definition
full of darkness, dark
Strong's Definition
opaque, i.e. (figuratively) benighted
Derivation: from G4655 (σκότος);
KJV Usage: dark, full of darkness
Thayer's Greek Lexicon
σκοτεινός (WH σκοτινος; see Iota), σκοτεινή, σκοτεινόν (σκότος), full of darkness, covered with darkness (from Aeschylus down): opposed to φωτεινός, Mat_6:23; Luk_11:34; Luk_11:36 (τά σκοτεινά καί τά φωτεινα, Xenophon, mem. 3, 10, 1; (cf. 4, 3, 4)).
Mounce Concise Greek Dictionary
σκοτεινός skoteinos 3x
dark, Mat_6:23 ; Luk_11:34 ; Luk_11:36
Abbott-Smith Greek Lexicon
σκοτεινός ( WH . -τινός ), -ή , -όν
( < σκότος ),
[in LXX chiefly for H2822 and cogn . forms;]
dark: opp . to φωτεινός , Mat_6:23 , Luk_11:34 ; Luk_11:36 .†
Moulton & Milligan — Vocabulary of the Greek NT
σκοτεινός [page 579]
dark : P Par 51 .19 (B.C. 159) (= UPZ i. p. 360, Selections , p. 20) εἰς <σ >κοτινὸν τόπον .
Liddell-Scott — Intermediate Greek Lexicon
σκοτεινός σκοτεινός, ή, όν [Etym: σκότος] "dark", Aesch. , Eur. , etc.; ἀνὰ τὸ σκοτεινόν in "the darkness", Thuc. of a person, "darkling, blind", Soph. , Eur. metaph. "dark, obscure", Eur. , Plat. :—so adv. -νῶς, Plat.
STEPBible — Tyndale Abridged Greek Lexicon
σκοτεινός (WH. -τινός), -ή, -όν
(σκότος), [in LXX chiefly for חֹשֶׁךְ and cogn. forms ;]
dark: opposite to φωτεινός, Mat.6:23, Luk.11:34, 36.†
(AS)