Nail Polish 

Typically, colored lacquer applied to fingernails (manicure) and toenails (pedicure) to make them look great! Used by both men and women.
* Traditionally worn by women on fingernails and toenails
* Becoming more popular for men on toenails

BB Couture and Man Glaze both offer nail polish designed for men in response to the increasing demand from guys for more masculine colors.
The toenail polish trend for men apparently got started by a number of male celebrities, possibly on the prompting of their wives or girlfriends (many pics online).
Erroneously belived to be a sign of a man being gay, in actuality it is becoming a popular style for many straight men.
It is considered to the be new "earring" for guys.

Nail Polish by Pedicure Dude November 12, 2009

nail in the coffin 

something that bring one closer to a seemingly unavoidable negative outcome such as death or defeat

Is this the final nail in the coffin for the coalition.

nail in the coffin by The Return of Light Joker August 16, 2009

coke-nail

Someones pinky nail grown-out long in order to snort cocaine

The criminal seemed to have a coke-nail

coke-nail by cheese man123 August 24, 2005

nail 

A syringe as in illicit drug use.

Yo Sid, got your nail man, lets get high.

nail by smurfsnork2k September 18, 2008

Rusty Nail 

scotch and drambuie mixed together

to barkeep : "rusty nail please, macallan."

Rusty Nail by carbombxhooligan December 13, 2004

Black nail polish

Black is the only nail polish color that both genders like to wear.

Girls wear black nail polish because it's such a bold and incredibly sexy color. Guys (cis) wear it mostly as a fashion trend statement (e.g. social media fad) or to symbolize that they are affiliated with a certain cultural movement (e.g. goth, emo). Only some guys wear it without any externally-motivated reasons.

There is also a noticeable difference in HOW each gender wears it. Guys (cis) often do it hastily. They have no intention to fill the polish in completely, and prefer it chipped. Most would opt for matte black. This is likely to distance themselves from actually partaking in a feminine hobby, or to follow the trend. Thus for guys, it is only a means to an end. When girls wear it though, it will look unironically gorgeous and catches people's eyes. Most will get it done professionally, or do it themselves with unprecedented perfection. Girls will take the extra mile to use a base coat, and put a top coat over the black polish to make it nice and glossy. Girls also like their nails long and shaped. They'd look—as you'd expect—feminine.

Guys rocking black nails isn't anything new or remarkable, but it would take some real balls (i.e. devotion) to paint them in a sincere impeccable fashion as a girl would.

Me: Guess what?? I just bought some black nail polish
Emily: LOL, are you going to become an eboy or what?
Me: Nah, that's stupid. I just thought it would be nice to try it out.
Emily: Suuuuure
Me: Like, I'm not even joking. I even bought a gel top coat and a nail buffer! Honestly, chipped nails are so overrated. I want some of that professional salon-quality nails, you know what I'm sayin'?
Emily: Ooooo, well send me send some pics when you have them done!

Me, 10 minute later: *sends photo*
Emily: Holy shit, that's legit better than anything I've ever done.

Black nail polish by Mary Mary Quite The Contrarian March 15, 2021

Naila 

(1)A term of South Asian origin, with roots in both Urdu and Malayalee, describing a perfect couple or a perfect love.

(2)Expression used casually in Grenada and other Caribbean islands as an inevitable pairing between a man and woman who didn't know each other before coming to the islands.

-"This couple getting married couldn't be more perfect for each other"
- "You're right. They're definitely a Naila!"

Naila by DrShadyZ May 15, 2010