A spambot is an automated computer program designed to assist in the sending of spam. Spambots usually create fake accounts and send spam using them, although in many cases it would be obvious that a spambot is sending it. This has led to the development of password-cracking spambots that are able to send spam using other people’s accounts.
Adding this to your .HTACCESS will help keep bots from posting comments on your WordPress blog, be sure to change yourdomain.com to your website address.
RewriteEngine On
RewriteCond %{REQUEST_METHOD} POST
RewriteCond %{REQUEST_URI} .wp-comments-post\.php*
RewriteCond %{HTTP_REFERER} !.*yourdomain.com.* [OR]
RewriteCond %{HTTP_USER_AGENT} ^$
RewriteRule (.*) http://%{REMOTE_ADDR}/$ [R=301,L]
Some more WordPress Tips: https://crunchify.com/category/wordpress/