# Line breaking in \newcommand

I defined a new command for highlighting some text parts:

\newcommand{\keyword}[1]{\colorbox{black!5}{#1}}


Unfortunately, when the text becomes to long it overlaps my margins. The keyword ignores the margin of the table, as well as the margin of the hole document.

\textbackslash\textbackslash do something \}) \}}
\\ \hline
\end{tabular}

\end{document}