Definition 1 or 2 (as John Adams used to say, often, you pays your money etc ..)
fantastic
adjective
1.
informal
extraordinarily good or attractive.
"they did a fantastic job"
synonyms: tremendous, remarkable, great, terrific, enormous, huge, striking, impressive, outstanding, phenomenal, monumental, overwhelming More
2.
imaginative or fanciful; remote from reality.
"fantastic hybrid creatures"
synonyms: fanciful, extravagant, extraordinary, irrational, wild, mad, absurd, far-fetched, nonsensical, incredible, unbelievable, unthinkable, implausible, improbable, unlikely, doubtful, dubious; More