Reference: http://www.binbaz.org.sa/mat/18730
Question: Concerning Ramadaan – O noble Shaykh – Does Gheebah and Nameemah render a person’s fast void in Ramadaan?
Response: Gheebah and Nameemah are two major sins, however they do not render the fast void. Nevertheless the person gains great sin because they are from the major sins, whether in Ramadaan or other than it, but they do not render the fast void.