Slang: Vulgar.

(used ironically as an interjection to indicate that a person or thing is considered unimportant or unimpressive): All I can say is BFD—her engagement is not exactly big news.
a person or thing of great importance or consequence; a big deal: It was the kind of BFD that impacted the whole industry.

Origin of BFD

initialism for big fucking deal Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2020

Examples from the Web for bfd