This is in the idea of the What is a Word/Group of Words group started by A Person with a new type of Word and Group of Words problems.
If a word is the best I call it an Explain word.
Use the following words to find the best words.
I
Don't
Know
Any
Not
Explain
Words
And
Am
Sad
About
It
Because I don't know any, there are no Not Explain Words in this whole problem, but there are many in the other problems.