wonderful vs marvellous

wonderful and marvellous both are adjectives.

Word	Noun	Adjective	Verb	Adverb
wonderful	No	Yes	No	No
marvellous	No	Yes	No	No

As adjectives, wonderful and marvellous are synonyms defined as:

wonderful and marvellous: extraordinarily good or great; used especially as intensifiers

Other synonyms of wonderful include fantastic, grand, howling, marvelous, phenomenal, rattling, terrific, tremendous, wondrous.

wonderful (adjective)	marvellous (adjective)
extraordinarily good or great; used especially as intensifiers	extraordinarily good or great; used especially as intensifiers
	too improbable to admit of belief
	being or having the character of a miracle