junk heap vs trash pile

junk heap and trash pile both are nouns.

Word	Noun	Adjective	Verb	Adverb
junk heap	Yes	No	No	No
trash pile	Yes	No	No	No

As nouns, junk heap and trash pile are synonyms defined as:

junk heap and trash pile: an accumulation of refuse and discarded matter

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

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