You can hide your profile from external search engines, such as Google, Yahoo, etc:
Click your name at the top of Pinterest then click Settings
Switch Search Privacy to Yes
Click Save Settings
Note: This change won't take effect immediately. When you turn this on, we add a tag to your profile to tell search engines to ignore the page. Your profile will remain in search results until the search engine returns to "re-index" the page. This may take several weeks to process.
To request a more immediate removal of an entire page from Google, follow Google's steps here.
Using a phone or tablet? Right now, you can't change search privacy in the app. For now, you'll need to log into Pinterest on the web in order to view and update this setting.