flagging vs accumulation

flagging and accumulation both are nouns.

Word	Noun	Adjective	Verb	Adverb
flagging	Yes	Yes	No	No
accumulation	Yes	No	No	No

As nouns, accumulation is a hypernym of flagging; that is, accumulation is a word with a broader meaning than flagging:

Other hypernyms of flagging include aggregation, assemblage, collection.

flagging (noun)	accumulation (noun)
a walk of flagstones	the act of accumulating
flagstones collectively	several things grouped together or considered as a whole
	(finance) profits that are not paid out as dividends but are added to the capital base of the corporation
	an increase by natural growth or addition

flagging (adjective)	accumulation (adjective)
weak from exhaustion