clock watcher vs idler

clock watcher and idler both are nouns.

Word	Noun	Adjective	Verb	Adverb
clock watcher	Yes	No	No	No
idler	Yes	No	No	No

As nouns, idler is a hypernym of clock watcher; that is, idler is a word with a broader meaning than clock watcher:

Other hypernyms of clock watcher include bum, do-nothing, layabout, loafer.

clock watcher (noun)	idler (noun)
a worker preoccupied with the arrival of quitting time	person who does no work