lark about vs lark

lark about is not a noun while lark is a noun.

Word	Noun	Adjective	Verb	Adverb
lark about	No	No	Yes	No
lark	Yes	No	Yes	No

As verbs, lark about and lark are synonyms defined as:

Other synonyms of lark about include cavort, disport, frisk, frolic, gambol, rollick, romp, run around, skylark, sport.

lark about (noun)	lark (noun)
	any carefree episode
	any of numerous predominantly Old World birds noted for their singing
	a songbird that lives mainly on the ground in open country; has streaky brown plumage
	North American songbirds having a yellow breast

lark about (verb)	lark (verb)
play boisterously	play boisterously