toxic dumpsite vs toxic waste dump

toxic dumpsite and toxic waste dump both are nouns.

Word	Noun	Adjective	Verb	Adverb
toxic dumpsite	Yes	No	No	No
toxic waste dump	Yes	No	No	No

As nouns, toxic dumpsite and toxic waste dump are synonyms defined as:

toxic dumpsite and toxic waste dump: a location where toxic wastes can be or have been disposed of (often illegally)

Other synonyms of toxic dumpsite include toxic waste site.

toxic dumpsite (noun)	toxic waste dump (noun)
a location where toxic wastes can be or have been disposed of (often illegally)	a location where toxic wastes can be or have been disposed of (often illegally)