marvellous vs terrific

marvellous and terrific both are adjectives.

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

As adjectives, marvellous and terrific are synonyms defined as:

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

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

marvellous (adjective)	terrific (adjective)
extraordinarily good or great; used especially as intensifiers	causing extreme terror
too improbable to admit of belief	extraordinarily good or great; used especially as intensifiers
being or having the character of a miracle	very great or intense