SPAM is often created by a bot rather than a human, one way for your WordPress website to distinguish between the two is to install a CAPTCHA plugin.
- Log in to WordPress
- Go to Plugins, then click Add New.
- Enter "CAPTCHA" in the 'Search Plugins' box
- Click on the name of the plugin to learn more about it
- After locating the plugin you prefer, click Install Now
Next steps
More info