double-tongued vs double-faced

double-tongued and double-faced both are adjectives.

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

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

double-tongued and double-faced: 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, duplicitous, Janus-faced, two-faced.

double-tongued (adjective)	double-faced (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
	(of fabrics) having faces on both sides