Adder

Boyd’s Bible Dictionary:

(viper). Used in the Bible for any poisonous snake known to the Jews, of which there were several species in Palestine. In Genesis 49:1717Dan shall be a serpent by the way, an adder in the path, that biteth the horse heels, so that his rider shall fall backward. (Genesis 49:17), the cerastes, or horned snake, is, from its habits, supposed to be alluded to. The cockatrice (Isa. 11:8; 14:29; 59:58And the sucking child shall play on the hole of the asp, and the weaned child shall put his hand on the cockatrice' den. (Isaiah 11:8)
29Rejoice not thou, whole Palestina, because the rod of him that smote thee is broken: for out of the serpent's root shall come forth a cockatrice, and his fruit shall be a fiery flying serpent. (Isaiah 14:29)
5They hatch cockatrice' eggs, and weave the spider's web: he that eateth of their eggs dieth, and that which is crushed breaketh out into a viper. (Isaiah 59:5)
; Jer. 8:1717For, behold, I will send serpents, cockatrices, among you, which will not be charmed, and they shall bite you, saith the Lord. (Jeremiah 8:17)), is adder and asp (Prov. 23:3232At the last it biteth like a serpent, and stingeth like an adder. (Proverbs 23:32); Psa. 58:44Their poison is like the poison of a serpent: they are like the deaf adder that stoppeth her ear; (Psalm 58:4)). In Psalm 140:33They have sharpened their tongues like a serpent; adders' poison is under their lips. Selah. (Psalm 140:3) and Proverbs 23:3232At the last it biteth like a serpent, and stingeth like an adder. (Proverbs 23:32), a species of viper is thought to be meant.

Concise Bible Dictionary:

There are four words thus translated.
1. akshub (Psa. 140:33They have sharpened their tongues like a serpent; adders' poison is under their lips. Selah. (Psalm 140:3)). This word occurs but once, and simply compares the wicked to adders who have poison under their lips. It cannot be identified.
2. pethen (Psa. 58:44Their poison is like the poison of a serpent: they are like the deaf adder that stoppeth her ear; (Psalm 58:4); Psa. 91:1313Thou shalt tread upon the lion and adder: the young lion and the dragon shalt thou trample under feet. (Psalm 91:13), reading in the margin of both asp). The wicked are compared to the deaf adder that stoppeth her ears. There is an old tradition that the adder sometimes laid one ear in the dust and covered the other with its tail; but they have no external ears: that all known adders can hear is well attested by those called serpent charmers, though some species are more easily attracted than others. The above name is held to point to the deadly Cobra. The same Hebrew word is translated asp in Deuteronomy 32:3333Their wine is the poison of dragons, and the cruel venom of asps. (Deuteronomy 32:33); Job 20:14,1614Yet his meat in his bowels is turned, it is the gall of asps within him. (Job 20:14)
16He shall suck the poison of asps: the viper's tongue shall slay him. (Job 20:16)
; Isaiah 11:88And the sucking child shall play on the hole of the asp, and the weaned child shall put his hand on the cockatrice' den. (Isaiah 11:8), simply pointing to it as poisonous or dangerous.
4. shephiphon (Gen. 49:1717Dan shall be a serpent by the way, an adder in the path, that biteth the horse heels, so that his rider shall fall backward. (Genesis 49:17)). This is identified with the Cerastes, or horned viper, so called because of having two short horns on its head. It is a small destructive snake, rarely more than two feet long. It is called in the margin an arrow-snake. It lies in holes or ruts and darts upon an animal passing: and this well agrees with the above text, where Dan is compared to “an adder in the path that biteth the horse heels, so that his rider shall fall backward” typical of apostasy and the power of Satan.