Guest Entries includes a simple Honeypot feature to help reduce spam via your front-end forms. Documentation around configuring can be seen under 'Configuration'.

Once you've enabled the Honeypot, ensure to add the field to your forms, like so:

{{ guest-entries:create collection="articles" }}
<h2>Create article</h2>
<input type="text" name="title">
<textarea name="content"></textarea>
<input type="hidden" name="zip_code" value=""> <!-- This is my honeypot -->
<button type="submit">Create</button>
{{ /guest-entries:create }}