say it: fan-TA-sti-klee
fantastically is an adverb meaning "exceedingly; extremely". It carries one recorded sense.
exceedingly; extremely
“she plays fabulously well”
“behind you the coastal hills plunge to the incredibly blue sea backed by the Turkish mountains”
Definitions, synonyms and semantic relations for fantastically come from Princeton University’s WordNet. The pronunciation comes from the CMU Pronouncing Dictionary. Commonness is measured against a corpus of everyday English. Full sources and licences.