say it: fan-TA-stik
fantastic is an adjective meaning "ludicrously odd". It carries 5 recorded senses.
ludicrously odd
“Hamlet's assumed antic disposition”
“fantastic Halloween costumes”
“a grotesque reflection in the mirror”
extraordinarily good or great; used especially as intensifiers
“a fantastic trip to the Orient”
“the film was fantastic!”
“a howling success”
“a marvelous collection of rare books”
“had a rattling conversation about politics”
“a tremendous achievement”
fanciful and unrealistic; foolish
“a fantastic idea of his own importance”
existing in fancy only
“fantastic figures with bulbous heads the circumference of a bushel”
extravagantly fanciful in design, construction, appearance
“Gaudi's fantastic architecture”
Definitions, synonyms and semantic relations for fantastic 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.