To begin with, case you already didn't know, kakko ii means "cool," kakko warui means "uncool." Though it's not that simple.
Kakko カッコIt all begins with the kakko, obviously, which they both share in common. This kakko isn't a real word, it's an abbreviation of the word kakkou 格好, and the word kakkou means "appearance," "outlook."
You often hear it used with pronouns like konna, sonna and anna, see:
- kon'na kakkou wa hazukashii こんな格好は恥ずかしい
This outfit is embarrassing.
- son'na kakkou de doko ni iku tsumori ka? そんな格好でどこに行くつもりか？
Where do you intend to go looking like that?
Kakko ii カッコイイ
The word kakko ii would then be actually an abbreviation of kakkou no ii 格好の良い, this ii 良い being an adjective meaning "good." Therefore, kakko ii and kakkou no ii would both be literally "good appearance" or "good outfit" or "looking good."
Most of the time, though, kakko ii is translated as "cool" in anime, because it's often used by teenagers talking about badassery and stuff.
Words like kawaii 可愛い, utsukushii 美しい and kirei 綺麗 are not exactly synonyms, but they can also be used to talk about good-looking people, and sometimes things.
Kakko warui カッコ悪い
The words kakko warui, kakko waru カッコ悪, and kakkou no warui 格好の悪い are literally the opposite, meaning "bad appearance." The warui 悪い here is also an adjective; it means "bad" and is often used for other things besides appearance.
If kakko ii is translated as "cool," then kakko warui would be translated as "lame." This, of course, can be used to talk about clothes, actions, appearances, outlooks, and so on.
A synonym with kakko warui is dasai ダサい, often times pronounced dassee ダッセェ. It literally means "lame" and is exclusively used for lame-looking people and things.
Kakko tsukete カッコつけて
With the verb tsukeru つける, "to attach," kakko tsukeru カッコつける would mean "to (try) to look good," "to be pretentious," and so on. It often shows up in anime when a character tries to appear better by saying some heroic line or doing someone a favor or almost dying in a battle.
This often shows up as:
- kakko tsukete かっこつけて
To try to look good.
- kakko tsuketeru tsumori? カッコつけてるつもり？
Are you trying to look good? (mocking)
(lit.: is your intention to look good?)
- kakko tsukeyagatte! カッコつけやがって！
[He] tried to look good! (blaming)
An important thing to note is that some adverbs are commonly used with the words kakko ii and kakko warui. Mostly with kakko ii. Here they are:
- sukoshi kakko ii 少しカッコイイ
A little cool.
- sugoku kakko ii すごくカッコイイ
Extremely cool. (comes from sugoi 凄い)
- chou kakko ii 超カッコイイ
These are used when just kakko ii alone doesn't cut it.
Difference Between Alphabets
A question you might have about these words is what's the difference between the various ways they can be written alternating between hiragana, katakana and kanji.
- kakko ii かっこいい
- kakko ii カッコイイ
- kakko ii カッコ良い
- kakko warui かっこ悪い
- kakko warui カッコ悪い
There is basically no difference. Use whichever is good.