noun
Casual katakana noun for a man or fellow. As a standalone word it can sound English-flavored or translation-like; it is especially easy to encounter in expressions such as ナイスガイ and タフガイ.
彼は気さくで、みんなからナイスガイと呼ばれている。
He is friendly and is called a nice guy by everyone.
あの映画の主人公は、典型的なタフガイだ。
The protagonist of that movie is a typical tough guy.