self-denigrating
adjective
self-den·i·grat·ing ˌself-ˈde-ni-ˌgrā-tiŋ 
: tending or serving to belittle or disparage oneself
a self-denigrating joke
As Nicholas, post-divorce, confronts a compositional writer's block, Hazel morphs into a sad, self-denigrating divorcee.
Karen Campbell
Karen Campbell
Word History
First Known Use
1958, in the meaning defined above