Let's understand what is adjective ?
The simplest definition of an adjective is that it is a word that describes or clarifies a noun. Adjectives describe nouns by giving some information about an object's size, shape, age, color, origin or material.
So the adjective is the given sentence would be:
Sentence: I disliked such behavior.
Adjective: Such; why? Because it describes the quality of the noun(behaviour).