duplicitous vs double-tongued

duplicitous and double-tongued both are adjectives.

Word	Noun	Adjective	Verb	Adverb
duplicitous	No	Yes	No	No
double-tongued	No	Yes	No	No

As adjectives, duplicitous and double-tongued are synonyms defined as:

duplicitous and double-tongued: marked by deliberate deceptiveness especially by pretending one set of feelings and acting under the influence of another

Other synonyms of duplicitous include ambidextrous, deceitful, double-dealing, double-faced, Janus-faced, two-faced.

duplicitous (adjective)	double-tongued (adjective)
marked by deliberate deceptiveness especially by pretending one set of feelings and acting under the influence of another	marked by deliberate deceptiveness especially by pretending one set of feelings and acting under the influence of another