Raven’s antispam – powerful and invisible fighter against comment spam. No set-up necessary, install and forget.
<h4>Details</h4>
Visitors with enabled JavaScript (99%+) see nothing – no annoying questions, no captcha, nothing. (Users with disabled JS see an additional text-field and a word that must be rewritten into the textfield.)
Note: this plugin is not able to check your trackbacks – to handle trackback spam, it’s necessary to use some other solution. (I recommend to disable trackbacks globally, since they rarely bring any benefit for your readers.) <a href="http://kahi.cz/wordpress/ravens-antispam-plugin/" rel="nofollow ugc">more…</a>.

Raven's Antispam

Powerful and invisible fighter against comment spam.

Dante Campbell

The DMN (Hush) plugin provides an easy way to disable comments on all post types in WordPress, including posts, pages, and custom post types. This is useful if you do not want to allow comments on your site, or if you want to disable comments for a specific period of time.
The plugin also removes all options related to comments from the WordPress dashboard, including the ability to enable comments on individual posts or pages. This helps to simplify the dashboard and prevent any confusion for users who may not be familiar with WordPress.
The DMN (Hush) plugin can be easily activated and deactivated from the WordPress dashboard, and requires no additional configuration or setup.

DMN (Hush)

The DMN (Hush) plugin allows you to disable comments on your WordPress site.

Raven's Antispam vs DMN (Hush)