lark about vs skylark

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

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

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

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

lark about (noun)	skylark (noun)
	brown-speckled European lark noted for singing while hovering at a great height

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