timeserving vs opportunist

timeserving is not a noun while opportunist is a noun.

Word	Noun	Adjective	Verb	Adverb
timeserving	No	Yes	No	No
opportunist	Yes	Yes	No	No

As adjectives, timeserving and opportunist are synonyms defined as:

timeserving and opportunist: taking immediate advantage, often unethically, of any circumstance of possible benefit

Other synonyms of timeserving include opportunistic.

timeserving (noun)	opportunist (noun)
	a person who places expediency above principle

timeserving (adjective)	opportunist (adjective)
taking immediate advantage, often unethically, of any circumstance of possible benefit	taking immediate advantage, often unethically, of any circumstance of possible benefit