unreliable vs treacherous

unreliable and treacherous both are adjectives.

Word	Noun	Adjective	Verb	Adverb
unreliable	No	Yes	No	No
treacherous	No	Yes	No	No

As adjectives, unreliable and treacherous are synonyms defined as:

unreliable (adjective)	treacherous (adjective)
not worthy of reliance or trust	dangerously unstable and unpredictable
dangerously unstable and unpredictable	tending to betray; especially having a treacherous character as attributed to the Carthaginians by the Romans
liable to be erroneous or misleading
lacking a sense of responsibility