すぎる is a verb that is used in Japanese to mean 'to exceed', or 'to go past'. It keeps this meaning when it is attached to other words, and creates the Japanese equivalent of saying that something is 'too much'.
すぎる can be joined to the ます stem of verbs, the stem form of
い-Adjectives (simply remove the い), or the stem form of
な-Adjectives (simply remove the
な).
頑張（がんば）りすぎるのは身体（からだ）に良（よ）くない。
Working too hard is not good for your health.
これは熱（あつ）すぎるよ。
This is way too hot.
俺（おれ）には田舎（いなか）は静（しず）かすぎる。
For me, the countryside is way too quiet.
With
すぎる, the
る is regularly omitted, with
すぎ being used by itself. This is a casual language pattern, and something you will hear all the time. This variation may be used with any word that
すぎる would usually be used with.
この犬（いぬ）、可愛（かわい）すぎ！
This dog is too cute!
There are a few rules that you will need to be careful about when using
すぎる. The first of these unique rules is using
すぎる with
ない. When linked to
ない, the い changes to さ, creating the structure
なさすぎる. This means 'too much not (A)', or more naturally in English 'not enough (A)'.
As with regular
ない forms,
では or
じゃ will be required when used after
な-Adjectives.
あの人（ひと）は私（わたし）のタイプじゃなさすぎる。
That person is DEFINITELY not type. (Literally 'they are too much not my type')
私（わたし）はお金（かね）がなさすぎる。
I don't have enough money. (Literally 'I have too much of no money')
この店（みせ）は商品（しょうひん）がなすぎる。
This store does not have enough goods. (This store has too much of nothing)
In the third example here, we can see that the さ has been omitted. This is technically not correct Japanese, but has become very common among young people, so it still sounds natural.
The second unique rule is when using
すぎる with
いい to mean 'too good'. Because
すぎる is used with the stem form of
い-Adjectives, you will need to remember that the stem form of
いい is not actually い, but よ. This means that よすぎる would be correct, while いすぎる is not.
この歌（うた）は良（よ）すぎる。
This song is too good.
Because
すぎる itself is a verb, it can also appear in the negative form, this confuses a lot of learners, and is something that needs to be practiced. Let's have a look at all of the ways that
すぎる could possibly appear with
ない.
学校（がっこう）に行（い）かなさすぎるから成績（せいせき）が落（お）ちた。
Because I don't go to school enough, my grades are going down. (Literally, I don't go too much)
彼（かれ）はトイレに行（い）かなさすぎない。
He doesn't not go to the toilet enough. (A double negative that becomes positive)
ゲームセンターには行（い）きすぎないでね。
Don't go to the arcade too often. (The negative focus is on 'too much', and sounds more like a request)
Because the meaning is different in each one of these sentences, depending on where the
ない is, and how many
ない's there are, you may need to be careful while reading these, until it starts to feel natural.