Vim: Disable syntax highlighter only for Markdown

First, tell Vim what file extension you want to set file type as markdown

autocmd BufRead,BufNewFile {*.markdown,*.mdown,*.mkdn,*.md,*.mkd,*.mdwn,*.mdtxt,*.mdtext,*.text} set filetype=markdown

**List of popular Markdown file extension from Superuser.com

Then, set syntax off for markdown

autocmd FileType markdown setlocal syntax=off spell

**spell is optional if you want to enable spell checker.

Here's a result: