nonmalignant tumor vs benign tumour

nonmalignant tumor and benign tumour both are nouns.

Word	Noun	Adjective	Verb	Adverb
nonmalignant tumor	Yes	No	No	No
benign tumour	Yes	No	No	No

As nouns, nonmalignant tumor and benign tumour are synonyms defined as:

Other synonyms of nonmalignant tumor include benign tumor, nonmalignant neoplasm, nonmalignant tumour.

nonmalignant tumor (noun)	benign tumour (noun)
a tumor that is not cancerous	a tumor that is not cancerous