timekeeper vs timepiece

timekeeper and timepiece both are nouns.

Word	Noun	Adjective	Verb	Adverb
timekeeper	Yes	No	No	No
timepiece	Yes	No	No	No

As nouns, timekeeper and timepiece are synonyms defined as:

timekeeper and timepiece: a measuring instrument or device for keeping time

Other synonyms of timekeeper include horologe.

timekeeper (noun)	timepiece (noun)
a measuring instrument or device for keeping time	a measuring instrument or device for keeping time
a clerk who keeps track of the hours worked by employees
(sports) an official who keeps track of the time elapsed