\documentclass{article}

\usepackage[T1]{fontenc}
\usepackage[locales=en,index,nomain]{glossaries}

\makenoidxglossaries

\newterm{aardvark}
\newterm{ætherial}
\newterm{ant}

\begin{document}
\gls{ætherial}, \gls{ant}, \gls{aardvark}.

\printnoidxglossary[type=index,sort=word,style=indexgroup]
\end{document}
