bling bling vs jewellery

bling bling and jewellery both are nouns.

Word	Noun	Adjective	Verb	Adverb
bling bling	Yes	No	No	No
jewellery	Yes	No	No	No

As nouns, jewellery is a hypernym of bling bling; that is, jewellery is a word with a broader meaning than bling bling:

bling bling: flashy, ostentatious jewelry
jewellery: an adornment (as a bracelet or ring or necklace) made of precious metals and set with gems (or imitation gems)

Other hypernyms of bling bling include jewelry.

bling bling (noun)	jewellery (noun)
flashy, ostentatious jewelry	an adornment (as a bracelet or ring or necklace) made of precious metals and set with gems (or imitation gems)