Collocations for fantastic - adj.

be, feel, look, smell, sound, taste
I felt fantastic after my swim. | This cake tastes fantastic.

really, truly
We had a really fantastic holiday.

absolutely, just, quite
The sense of freedom was absolutely fantastic.

be, look, sound

rather
It may sound rather fantastic, but it''s the truth.

increasingly
The plot gets increasingly fantastic as the film goes on.