tumour vs neoplasm

tumour and neoplasm both are nouns.

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

As nouns, tumour and neoplasm are synonyms defined as:

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

Other synonyms of tumour include tumor.

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