Haitlin 

When you are hating on Caitlin

Girl: that girl keeps on eating in the lecture theatre

Boy: why you be Haitlin?

Haitlin by Haitlersgonnahait January 21, 2013

Among us hairline 

Only the most elite members of society are seen with these. It is a privilege, but also a massive responsibility to have an among us hairline. The among us hairline is a symbol of leadership and superiority, which is why you have never seen one, for holders of the among us hairline do not show themselves amongst average human beings.

Bro got that among us hairline, damn.

Among us hairline by ChardNard420 September 24, 2021

Fucked Up Hairline 

When your hairline looks awful or ghastly.
This may even cause others who see it to have a nauseating effect due to witnessing such an atrocity.

Drew aka Drewbacca perfectly exemplifies this definition:
His hairline resembles a staircase, now this wasn't done on purpose hence the "Fucked Up Hairline"

Visual Evidence:
Exhibit A:
http://farm4.static.flickr.com/3485/3183251697_f95103f461.jpg
Exhibit B:
http://farm4.static.flickr.com/3128/3178603647_11c3f91e80.jpg

Fucked Up Hairline by Hypebeast2009 January 10, 2009

Hairline 

The line where your hair starts. For some reason, dumbasses like to make fun of people's hairlines when they don't really matter.

Kid: U HaVe a rachet hairline!
Sane person: Why does it matter?

Hairline by Racist21 June 3, 2015

hairline perm

Usually said to someone with the name xander, that has a perm and a shitty hairline.

"Look at that kids shitty as hairline"
"Ya, he's trying to hide it with his perm"
"Just because of his hairline perm, I'm gonna assume his name is xander

hairline perm by Borgus G peenerton December 31, 2020

hairline 

something that Jojo Siwa doesn't have

I haven't been to urban dictionary since the last time Jojo Siwa had a hairline.

hairline by sisterslang March 21, 2020

Hairline Malfunction 

Literally Ben perrins

Look at that hairline Malfunction, he is fiiiit

Hairline Malfunction by Pigeon eater78 June 26, 2021