phrase vs like clockwork

phrase is a noun but like clockwork is not a noun.

Word	Noun	Adjective	Verb	Adverb
phrase	Yes	No	Yes	No
like clockwork	No	No	No	Yes

phrase (noun)	like clockwork (noun)
dance movements that are linked in a single choreographic sequence
an expression consisting of one or more words forming a grammatical constituent of a sentence
a short musical passage
an expression whose meanings cannot be inferred from the meanings of the words that make it up

phrase (verb)	like clockwork (verb)
put into words or an expression
divide, combine, or mark into phrases

phrase (adverb)	like clockwork (adverb)
	with regularity and precision