Islamic concepts

Musrif — excessive sinner

extravagant, go too far

act extravagantly, act recklessly, transgress, neglect

http://corpus.quran.com/qurandictionary.jsp?q=srf#(39:53:4)

isrāf إسراف

Say, "O My servants who have transgressed against themselves [by sinning], do not despair of the mercy of Allah . Indeed, Allah forgives all sins. Indeed, it is He who is the Forgiving, the Merciful." 39:53