\documentclass{article}

\usepackage[nonumberlist]{glossaries-extra}

\makeglossaries

\newabbreviation[description={Fast Fourier transform}]{fft}{fft}{fast Fourier transform}

\begin{document}

\gls{fft}

\glspl{fft}

\GLS{fft}

\GLSpl{fft}

\end{document}