fanfuckingtastic adjective 1exclamation 1forms 2 adjective1 •(slang, vulgar) Fantastic; great.A: How is your vacation going? B: It is fanfuckingtastic, and I wish it could last twice as long. exclamation1 •(slang, vulgar) Fantastic; great.A: Austin just broke the faucet again. B: Fanfuckingtastic. Shouldn't someone already have fired that guy by now? formsmore fanfuckingtastic · most fanfuckingtastic