How to eliminate extra space around binary math operator

Question

As an example, consider the plus sign (+). The code $x + y$ generates x + y. How can you make it look like x+y? In other words, how can you treat + like a letter rather than an operator? I'm looking for a local solution rather than a global one.

MWE :

\documentclass{article}
\begin{document}
$x + y$
\end{document}

Answer 1

\documentclass{article}
\begin{document}
$x + y$

$x{+}y$
\end{document}