Tmesis
/təˈmiːsɪs/
Definition 1 of 1
Pro Tip 1/3Informal Usage
Tmesis is most common in informal speech and writing to add emphasis or humor. 
'This is going to be legen-wait for it-dary!' shows tmesis for dramatic effect.
Pro Tip 2/3Creative Speech
Using tmesis can make language more creative by breaking expected word patterns. 
The phrase 'abso-bloomin-lutely' is an inventive use of tmesis.
Pro Tip 3/3Speech Emphasis
Tmesis draws attention to the inserted word for stronger emphasis than the original word. 
Saying 'un-believably great' rather than 'unbelievably great' emphasizes the greatness.