To decrease receiving spam through your Contact Form, you need to add CAPTCHA protection. This adds the cryptic code you must enter on many websites today including on this website’s contact page. This is intended for sites specifically using the Contact Form 7 WordPress plugin.
1) You will need to install the Really Simple CAPTCHA plugin.
2) You must go to the Contact Admin page within wp-admin. Edit the intended Contact Form and use generate tag. You will then want to add code similar to the following within the form itself except for using the numbers from the generate tag results:
<p>[captchac captcha-464 fg:#00ff00 bg:#000000]
Enter the code from above
[captchar captcha-464 4/4]
NOTE: The reason for adding the colors (foreground & background) is to make the code more visible. Your choice of what to use or leave off but, just a suggestion. After you save the form you should now have CAPTCHA protection.