red hair

字面意思是红头发，没错：

Mary's red hair always made her conspicuous at school.

玛丽的红头发在学校里总是很惹眼。

I recognized her by her red hair.

我从她的红头发认出了她。

I recollected that she had red hair.

我记得她有一头红发。

He married a beautiful redhead.

他与一个漂亮的红发女郎结婚了。

Moretti ran a hand through his disordered red hair.

莫雷蒂用手理了理他那一头凌乱的红发。

I tried to fantasize about Christine: those wondering blue eyes, that coppery red hair of hers.

我对克里斯蒂娜想入非非：她那双充满好奇的蓝眼睛、那头红棕色的秀发令人着迷。

He had been greeted by the sight of his mother, her red hair wildly streaming.

他最先看见了他母亲，她红色的头发在风中狂舞。

I had always had a thing about red hair

我一直很讨厌红头发。

red hair 不单单指一个人的发色是红色的，延伸之意是看起来脾气不好的那样。很多地方也曾经说过，一个人red hair就是脾气特不好。在平时交流当中，人们所使用更多的却是它的引申意思

例句：

I'm not happy today. I met a red hair guest.

我今天很不开心，遇到了一个脾气古怪的客人。

I've known her for years. She is not a red hair person.

我认识她很多年了，她不是那种脾气古怪的人。

I don’t like to communicate with the red hair guy.

我不喜欢跟脾气古怪的人交流。