Put a slash through a word

Load the cancel package and use \cancel{word}. Most of the commands from the package work in both math and text modes.

Following frabjous' advice, I seem to have discovered a bug in the cancel package: Cancelling at the start of a paragraph only works if you add \leavevmode.

\documentclass{article}

\usepackage{cancel}

\begin{document}

Some text.

% \cancel{Some text.}% Doesn't work
\leavevmode\cancel{Some text.}% Works

\end{document}

You might like to try the ulem package and use the command \sout{word} to strikeout a word.