postponement vs time lag

postponement and time lag both are nouns.

Word	Noun	Adjective	Verb	Adverb
postponement	Yes	No	No	No
time lag	Yes	No	No	No

As nouns, postponement and time lag are synonyms defined as:

Other synonyms of postponement include delay, hold, wait.

postponement (noun)	time lag (noun)
act of putting off to a future time	time during which some action is awaited
time during which some action is awaited