On December 6, 2017, about 2207 eastern standard time, Spirit Airlines flight NKS265, an Airbus 321-231, N670NK, encountered turbulence during approach to land at Fort Lauderdale-Hollywood International Airport (KFLL), Fort Lauderdale, Florida. One flight attendant received a serious injury and the airplane was not damaged. The regularly scheduled domestic passenger flight was operating under the provisions of 14 Code of Federal Regulations Part 121 from Atlantic City International Airport (KACY), Atlantic City, New Jersey, to KFLL. According to the flight crew, the flight encounter the severe turbulence while descending through about 12,000 shortly after entering instrument meteorological conditions. There had been no reports of turbulence in the area and the seat belt sign was activated. At the time of the turbulence encounter, the flight attendants (FA) were conducting their final cabin checks when all five FAs were thrown to the floor. One FA sustained an ankle injury and remained on the floor for the remainder of the flight. After landing, all five FAs were transported to the hospital where the FA was diagnosed with a medial and posterior malleolar facture.