double-tongued vs duplicitous

double-tongued and duplicitous both are adjectives.

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

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

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

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

double-tongued (adjective)	duplicitous (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