WordNet sense 1 (for a special service or occasion):

special

WordNet sense 2 (unusual or striking):

remarkable, singular

WordNet sense 3 (marked by an uncommon quality; especially superlative or extreme of its kind):

rare, uncommon

WordNet sense 4 (exceedingly or unbelievably great):

fantastic, phenomenal

WordNet sense 5 (extraordinarily good; used especially as intensifiers):

marvelous, terrific, wonderful

WordNet sense 6 (far beyond what is usual in magnitude or degree):

exceptional, prodigious

WordNet sense 7 (far more than usual or expected):

over-the-top, sinful

WordNet sense 8 (not within reasonable limits):

immoderate

WordNet sense 9 (not usual or common or ordinary):

unusual