neoplasm vs tumour

neoplasm and tumour both are nouns.

Word	Noun	Adjective	Verb	Adverb
neoplasm	Yes	No	No	No
tumour	Yes	No	No	No

As nouns, neoplasm and tumour are synonyms defined as:

neoplasm and tumour: an abnormal new mass of tissue that serves no purpose

Other synonyms of neoplasm include tumor.

neoplasm (noun)	tumour (noun)
an abnormal new mass of tissue that serves no purpose	an abnormal new mass of tissue that serves no purpose