In Japanese, almost any type of word can be attached to a noun to modify the meaning, or describe the qualities of that noun. However, depending on the type of word used, conjugation rules will differ slightly. For い-Adjectives
, they are simply attached to the front of the noun in their standard (dictionary) form.
Caution: When identifying what an い adjective is, and what is not, remember that an い-Adjectives い will ‘always’ be outside of the kanji in the word.
面白（おもしろ）い - The い is outside the kanji, so it is definitely an い-Adjective.
綺麗（きれい） - The い is inside of the kanji, so it is definitely not an い-Adjective.
There are some, but very few exceptions.
嫌（きら）い - The い is outside of the kanji, but this is an な-Adjective.