Question

but the fattest is not any degree? means its not coming in any parts of degrees neither in comparative nor in superlative ​

Answer 1

Answer:

superlative degree is the fastest

Answer 2

Answer:

No, the comparative degree of fat is fatter and superlative degree is fattest.

Examples:

comparative: I am fatter than her.

superlative: I am the fattest in my family.