junk heap vs rubbish heap

junk heap and rubbish heap both are nouns.

Word	Noun	Adjective	Verb	Adverb
junk heap	Yes	No	No	No
rubbish heap	Yes	No	No	No

As nouns, junk heap and rubbish heap are synonyms defined as:

junk heap and rubbish heap: an accumulation of refuse and discarded matter

Other synonyms of junk heap include garbage heap, junk pile, refuse heap, scrapheap, trash heap, trash pile.

junk heap (noun)	rubbish heap (noun)
an accumulation of refuse and discarded matter	an accumulation of refuse and discarded matter