Dangerous
Risky
い adjective
This is a single kanji with an い on the end, meaning you know it's probably an adjective. What's the adjective form of dangerous? It's dangerous.
Since this word consists of a kanji with hiragana attached, you can bet that it will use the kun'yomi reading. You didn't learn that reading with this kanji, so here's a mnemonic to help you: Someone is in danger! It's poor old abe (あぶ) Lincoln. You try to save him, yelling out 危ないよ！！！！, but he gets shot in the back of the head anyways.
危ない事
a dangerous matter, a dangerous thing
危ない所
a dangerous place
危ない物
a dangerous item
命が危ない
one's life is in danger
京都が危ない
Kyoto is dangerous
私の方が危ない
I'm in more danger, I'm more dangerous
ちょっと危ない
a bit dangerous
かなり危ない
considerably dangerous
とても危ない
very dangerous
本当に危ない
really dangerous
実に危ない
truly dangerous
見た目以上に危ない
more dangerous than it looks
これは危ない
this is dangerous
夜は危ない
it is dangerous at night
ここは危ない
it is dangerous here
危ない！気をつけて。
Be careful! Watch out!
スピードを出しすぎると危ないですよ。
Driving too fast is dangerous, you know.
夜道を一人で歩くのは危ないです。
Walking alone on the streets at night is dangerous.