An adjective is a word that modifies a noun. It describes the qualities of a noun, such as size, shape, color, mood, nationality, age, etc. In the case of different, it can be used to compare items or people that are not the same, or not comparable.
1. This restaurant offers a different menu than the one next door.
2. None of the two versions were exactly the same, they were slightly different.
3. The employee in charge of this task needs to think differently than they did before.
The word different is rarely used in the comparative degree, as it normally implies that there are two things being compared, rather than more than two. It also shouldn’t be used to describe physical characteristics, such as size or shape. For example, it would not be correct to say 'This chair is different size than the other one'.