Remove more or […] text from short post

The codex is your friend and should be your first stop 🙂

The [...] is added by the_excerpt(). There is a filter supplied called the excerpt_more filter that is specifically included to customize the read more text after the excerpt

To remove the [...] after the excerpt text, you can do the following

function new_excerpt_more( $more ) {
    return '';
}
add_filter('excerpt_more', 'new_excerpt_more');