subtle vs pernicious

subtle and pernicious both are adjectives.

Word	Noun	Adjective	Verb	Adverb
subtle	No	Yes	No	No
pernicious	No	Yes	No	No

As adjectives, subtle and pernicious are synonyms defined as:

subtle and pernicious: working or spreading in a hidden and usually injurious way

Other synonyms of subtle include insidious.

subtle (adjective)	pernicious (adjective)
working or spreading in a hidden and usually injurious way	working or spreading in a hidden and usually injurious way
difficult to detect or grasp by the mind or analyze	exceedingly harmful
able to make fine distinctions