fantastic vs wonderful

fantastic and wonderful both are adjectives.

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

As adjectives, fantastic and wonderful are synonyms defined as:

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

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

fantastic (adjective)	wonderful (adjective)
extraordinarily good or great; used especially as intensifiers	extraordinarily good or great; used especially as intensifiers
extravagantly fanciful in design, construction, appearance
ludicrously odd
existing in fancy only
fanciful and unrealistic; foolish