A sanction from Google is reflected in a negative impact on the search ranking of a website because it does not comply with the updates of Google algorithms and / or manual review.

The penalty can be a byproduct of an algorithm update or an intentional penalty at the hands of the negative SEO / Black Hat SEO.

A Google penalty is the negative impact on a website's search rankings based on updates to Google's search algorithms or manual review....

A Google penalty is the negative impact on a website's search rankings based on updates to Google's search algorithms or manual review. The penalty can be a by-product of an algorithm update or an intentional penalization for various black-hat SEO techniques.

Google Penalty is a punishment of google for websites that violate the law; the cognitive signs of this punishment are :
_ Reduce traffic
_ The number of links is indexed down significantly
_ The crawling speed is reduced

negative impact on a website's search rankings

Hello
Google Penalty is a negative effect on  website . which can be course due to some inappropriate activity on website .

google penalty is a slang which is used when you use some black hat method for the website.