Foreigner
Outsider
noun
An "outside person" is a foreigner. This word is fairly common, though it's not super polite, either. It's okay most of the time, but it can be used derogatorily depending on the situation. The more polite version is 外国人 (outside country person) but you won't learn that until you learn the kanji for 国.
This is a jukugo word, which usually means on'yomi readings from the kanji. Since 人 has two on'yomi readings, here's a mnemonic to help you remember which one to use:
Who's the foreigner? Well obviously the guy wearing jeans (がいじん)!
外人カップルとダブルデートをした。
We had a double date with a foreign couple.
アフターパーティーには外人がたくさんいた。
There are lots of foreigners at the after party.
バーにいた外人さんがウィスキーをおごってくれたんです。
The foreigner at the bar bought me a glass of whiskey.