slowdown vs lag

slowdown and lag both are nouns.

Word	Noun	Adjective	Verb	Adverb
slowdown	Yes	No	No	No
lag	Yes	No	Yes	No

As nouns, slowdown and lag are synonyms defined as:

Other synonyms of slowdown include retardation.

slowdown (noun)	lag (noun)
the act of slowing down or falling behind	the act of slowing down or falling behind
	one of several thin slats of wood forming the sides of a barrel or bucket
	the time between one event, process, or period and another

slowdown (verb)	lag (verb)
	throw or pitch at a mark, as with coins
	cover with lagging to prevent heat loss
	hang (back) or fall (behind) in movement, progress, development, etc.
	lock up or confine, in or as in a jail