common viper vs adder

common viper and adder both are nouns.

Word	Noun	Adjective	Verb	Adverb
common viper	Yes	No	No	No
adder	Yes	No	No	No

As nouns, common viper and adder are synonyms defined as:

common viper and adder: small terrestrial viper common in northern Eurasia

Other synonyms of common viper include Vipera berus.

common viper (noun)	adder (noun)
small terrestrial viper common in northern Eurasia	small terrestrial viper common in northern Eurasia
	a machine that adds numbers
	a person who adds numbers