I know that we can use the intensifier "fantastically" in constructions such as:
- The team played fantastically well.
- The car is fantastically expensive.
But can we say
- He was fantastically thirsty
-
4You can if you want to, but extremely is more usual. Something that is fantastic is, in some way, unbelievable. "Unbelievably thirsty" would work, so I suppose that "fantastically thirsty" is allowable. – Mick Dec 4 '17 at 15:14
"Fantastically" in its natural, straightforward form has strong, positive connotations. It can be used with sarcasm, as in your second example, mocking the extreme levels of some property, making something negative appear positive.
So, unless your scenario calls for some sort of sarcasm/mockery, don't use it like that.
But depending on the context...
...and besides, anchovies make me fantastically thirsty. Give me a can and I can literally out-drink everyone.
or
"I'm so envious about your trip to Africa!"
"Yes, it was wonderful. We had the pleasure of having all our luggage stolen on the first stop, then we had three days of sightseeing the insides of genuine jail, for having no passports which were with the luggage, then we were offered the pleasure of walking thirty miles through the desert back to the city. We nearly got lost in the harsh beauty of wild Africa, chased a wonderful lion away with sticks, finally, fantastically thirsty found our way to the consulate to be sent back home. You would have loved it!"
