peep vs let loose

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

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

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

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

peep (noun)	let loose (noun)
a secret look
the short weak cry of a young bird

peep (verb)	let loose (verb)
appear as though from hiding	express audibly; utter sounds (not necessarily words)
make high-pitched sounds	turn loose or free from restraint
speak in a hesitant and high-pitched tone of voice
look furtively
cause to come into view