So-called i-adjectives end with the hiragana character い.
If an adjective is a true i-adjective, the final will change as the adjective is conjugated. For example:
長い = long
長くない = not long
長かった = was long
長くなかった = was not long
To modify a noun with an i-adjective, attach the adjective form directly to the noun:
長い紐 the long string
長い紐 the string that isn't long
- Na-adjectives that end in い : There are a handful of na-adjectives that end in い. These have to be identified and memorized when you encounter them. (But again, there aren’t many.) The most common one is きれい な.
- Do not attach だ to i-adjectives.