junk heap vs scrapheap

junk heap and scrapheap both are nouns.

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

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

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

junk heap (noun)	scrapheap (noun)
an accumulation of refuse and discarded matter	pile of discarded metal
	an accumulation of refuse and discarded matter