Quick Definition
ἔχιδνα, ης, ἡ n.f. a serpent, snake, viper
Strong's Definition
of uncertain origin; an adder or other poisonous snake (literally or figuratively)
KJV Usage: viper
UBS Dictionary of the Greek New Testament
noun, f. | -ης
4.53 · Animals · Reptiles and Other 'Creeping Things'
asp, cobra, viper kind of poisonous snake; associated with lurking danger The terms ἀσπίς and ἔχιδνα[a] may be used to refer to almost any kind of poisonous snake, and since at least some type of poisonous snake occurs in practically all parts of the world, there is usually little difficulty involved in finding an appropriate term. One can, however, always employ a descriptive expression, for example, ‘a snake whose bite causes death.’
88.123 · Moral and Ethical Qualities and Related Behavior · Bad, Evil, Harmful, Damaging
evil person, viper, snake (a figurative extension of meaning of ἔχιδνα[a] ‘viper,’ 4.53) a dangerous and despised person One must exercise due caution in rendering ἔχιδνα in MAT 12:34 and ὄφις[b] in MAT 23:33, since in some cultures snakes are regarded as being particularly wise and clever, and therefore an expression such as ‘brood of vipers’ could be a compliment. In some languages important distinctions are made between different types of snakes, and therefore connotations may vary considerably.
UBS Dictionary of the Greek New Testament © United Bible Societies, licensed CC BY-SA 4.0.
Thayer's Greek Lexicon
ἔχιδνα, -ης, 7, α viper: Acts xxviii. 3 (Hes., Hadt., Tragg., Arstph., Plat., al.); γεννήματα ἐχιδνῶν offspring of vipers (anguigenae, Ovid, metam. 3,531), addressed to cunning, malignant, wicked men: Mt. iii. 7; xii. 34; ΧΧΙ 99: kK AMS Wee
Mounce Concise Greek Dictionary
ἔχιδνα echidna 5x
a viper, poisonous serpent, Acts 28:3; used also fig. of persons, Mt. 3:7; 12:34; 23:33; Lk. 3:7*
Abbott-Smith Greek Lexicon
** ἔχιδνα, -ης, ἡ,
[in OT (Aq.), Is 59:5*;]
a viper: Ac 28:3; metaph., γεννήματα ἐχιδνῶν, Mt 3:7 12:34 23:33, Lk 3:7.†
Moulton & Milligan — Vocabulary of the Greek NT
ἔχιδνα. Ramsay (Lue, p. 63 ff.) has shown that by the ἔχιδνα of Ac 288 we are probably to understand a constrictor snake, closely resembling a viper, without poison-fangs, which fixes its teeth firmly into the human skin so as to hang on, without, however, doing any real injury to the skin. The verb καθῆψεν in the sense of ‘‘ fastened upon” rather than ‘‘ bit” (‘‘momordit,” Blass) is therefore correctly applied to it, as against Harnack Lekas der Aret, p. 123 f. (E. Tr., p. 177 f.). On γεννήματα ἐχιδνῶν as equivalent to the simple ἔχιδναι in Mt 37 see McNeile ad /., following Nestle in ZV7'/V xiv. p- 267 f.
Liddell-Scott-Jones — Greek-English Lexicon
ἔχιδνα (echidna) — snake. ἔχιδν-α, ἡ, (ἔχις) viper, [Refs 5th c.BC+]; probably of a constrictor snake, [NT+5th c.BC+]; ἱματισμένη ἔ., of woman, [Refs 2nd c.AD+]; γεννήματα ἐχιδνῶν brood of vipers, term of reproach, in [NT]
II. proper name of a monster, [Refs 8th c.BC+]