knock about vs batter

knock about is not a noun while batter is a noun.

Word	Noun	Adjective	Verb	Adverb
knock about	No	No	Yes	No
batter	Yes	No	Yes	No

As verbs, knock about and batter are synonyms defined as:

Other synonyms of knock about include buffet.

knock about (noun)	batter (noun)
	a liquid or semiliquid mixture, as of flour, eggs, and milk, used in cooking
	(baseball) a ballplayer who is batting

knock about (verb)	batter (verb)
strike against forcefully	make a dent or impression in
be around; be alive or active	strike violently and repeatedly
	strike against forcefully