repeat vs let loose

repeat is a noun but let loose is not a noun.

Word	Noun	Adjective	Verb	Adverb
repeat	Yes	No	Yes	No
let loose	No	No	Yes	No

As verbs, let loose is a hypernym of repeat; that is, let loose is a word with a broader meaning than repeat:

Other hypernyms of repeat include emit, let out, utter.

repeat (noun)	let loose (noun)
an event that repeats

repeat (verb)	let loose (verb)
happen or occur again	express audibly; utter sounds (not necessarily words)
to say, state, or perform again	turn loose or free from restraint
to say again or imitate
make or do or perform again
repeat an earlier theme of a composition
do over