I recently shared a post on how to delete a Facebook account permanently. But today, I want to share how you can easily cancel or delete a Google+ account without having any effect on other Google services (gmail, adsense, adword, docs etc.) you subscribed to. You can also check: How to Disable Google Plus Email and SMS Notifications
1) Log in into your Google Plus account
2) Locate and click on your account name or email address on the upper right corner and click on ‘Account Settings’
3) In the account service page, locate and click on ‘Delete profile and remove associated social features’.
4) On the next page, select ‘Delete Google+ content’ and then click ‘Remove selected services’.
That’s all. Once you’ve compete the steps outlined above, you’re no longer among Google+ services or its circles. But you can rejoin back in the future if you desire to.