time-tested vs tested

time-tested and tested both are adjectives.

Word	Noun	Adjective	Verb	Adverb
time-tested	No	Yes	No	No
tested	No	Yes	No	No

As adjectives, time-tested and tested are synonyms defined as:

Other synonyms of time-tested include tried, tried and true.

time-tested (adjective)	tested (adjective)
tested and proved to be reliable	tested and proved useful or correct
	tested and proved to be reliable