marvelous vs fantastic

marvelous and fantastic both are adjectives.

Word	Noun	Adjective	Verb	Adverb
marvelous	No	Yes	No	No
fantastic	No	Yes	No	No

As adjectives, marvelous and fantastic are synonyms defined as:

marvelous and fantastic: extraordinarily good or great; used especially as intensifiers

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

marvelous (adjective)	fantastic (adjective)
extraordinarily good or great; used especially as intensifiers	extraordinarily good or great; used especially as intensifiers
too improbable to admit of belief	extravagantly fanciful in design, construction, appearance
being or having the character of a miracle	ludicrously odd
	existing in fancy only
	fanciful and unrealistic; foolish