Many
Much, Lots Of
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 many? It is also many (or you could say much). Speaking of which, there are so many kanji to learn, ammiright?
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:
Think of something that is many. Doesn't matter what it is as long as you imagine a ridiculous number of them. Many of them. So many that they start avalanching into you and crushing you. The last thing you yell is "おお!!!" as you get smushed.
人が多い
there are many people
車が多い
there are many cars
人口が多い
the population is large
ニューヨークは人が多い。
There are many people in New York.
「自分は正しい」と言う人は多い。
There are many people who say they're right.
この村は、日本一人口が多い村です。
This village is the most populated village in Japan.