reorganization vs shake-up

reorganization and shake-up both are nouns.

Word	Noun	Adjective	Verb	Adverb
reorganization	Yes	No	No	No
shake-up	Yes	No	No	No

As nouns, reorganization and shake-up are synonyms defined as:

reorganization and shake-up: the imposition of a new organization; organizing differently (often involving extensive and drastic changes)

Other synonyms of reorganization include reorganisation, shakeup.

reorganization (noun)	shake-up (noun)
the imposition of a new organization; organizing differently (often involving extensive and drastic changes)	the imposition of a new organization; organizing differently (often involving extensive and drastic changes)
an extensive alteration of the structure of a corporation or government