monotopical 

Someone who always talks about the same subject, or keeps the same topic active for weeks.

That guy is so monotopical nobody wants to talk to him any more.

monotopical by Herculoid February 20, 2010

monotypical

A "single-minded" form of expressing prejudiced/derisive ideas or beliefs.

Monotypical ideas are formed by using just one portion of the brain, whereas stereotypical thinking utilizes both sides.

monotypical by QuacksO October 25, 2018