What is a word like abso-bloomin-lutely called?

A word like "abso-bloomin-lutely" is called a "reduplicative compound". It is a word that is formed by repeating a word or part of a word, often with some variation. In this case, the word "abso-" is repeated, and the word "bloomin-" is added in between. This type of compound is often used to add emphasis or to create a humorous effect.