noobtube 

The name given, by players of the game CoD4, to the assault rifle mounted grenade launcher do to the fact that it is seen as requiring little skill to use and the fact that it is, in fact, a tube.

Also, the use of said grenade launcher.

(JWilkesBoof kills HonestFive with an M203 grenade)
HonestFive: "Oh come on man don't noobtube!"

noobtube by Abhorent Aardwolf April 15, 2008

noobtube 

A gaming action used in online shooters (i.e. COD MW2, etc..) involving the use of a rifle mounted grenade launcher to achieve easy kills.

Xray-479:

"Awesome, check out that replay, got you with my launcher from across the map while in a prone camping position; I am the luckiest nube ever"

TBAG: "Dammit, there goes my f----ng kill streak, damned noobtuber"

noobtube by SGT-T-BAG June 5, 2010

Noobtube 

A grenade launcher mounted underneath a gun, most commonly an assault rifle, in Call of Duty games. The word "Noobtube" comes from the player using it being a "noob" and the fact that the grenade launcher looks like a tube; hence the word Noobtube. Noobtubes carry 2 grenades that can also be refilled using the Scavenger perk or the highly despised One Man Army perk. They have a very large blast radius and enormous damage, leading to one hit kills even if the grenade lands 10-15 from the enemy. The most hated thing you can do with the Noobtube, is to join a domination game and shoot the Noobtube across the map at the beginning of the game into the enemies flag closest to their spawn, earning a 2-6 hit kill with one shot. The players using the Noobtube are called Noobtubers and are hated by many players in the gaming community because of the weapon requiring little effort to get kills with because of its high damage and blast radius. A Noobtubers K/D is usually quite high and they commonly achieve higher ranked killstreaks, (Pave low, Chopper gunner, AC-130, ect).

(Immature enemy)
Noobtuber kills enemy-
Enemy: OMG! Learn how to use a gun you dumb faggot Noobtuber!
Noobtuber: I'm just trying to play the objective and get kills, chill!
Enemy: (rage quits and joins a new game)
(Mature enemy)
Noobtuber kills enemy-
Enemy: (grunts in annoyance) that Noobtube is annoying but is is a weapon in the game and he is allowed to use it.
Noobtuber: Thank you! Someone understands! Want to be my friend?

Enemy: Sure!
(Noobtuber and enemy become friends and start a clan)

Noobtube by Infernostar December 25, 2012

NoobTube 

When some fagg on Cod uses a greanade launcher and kills you

Damn That bitch just noobtubed me

NoobTube by The Pizza man at your door March 4, 2010

Noobtube 

Any grenade launcher attachment used in Call of Duty Modern Warfare, employed by n00bs of the highest caliber.

That n00b wont stop with the fucking Noobtube!!!!

Noobtube by that nigga cross the street November 21, 2011

noobtube 

The nickname of the the Halo or Halo II rocket launcher when used "noobily" by a noob that hogs the rocket launcher(the most powerful weapon in the game) and tends to "camp" but ultimately loses the battle and/or all his dignity and reputation.

"Your noob tactics only encourage us to severely own you in a few seconds and you won't have your stupid noobtube to help you, think fast ya nooblet!"

noobtube by Thy Froogle King March 22, 2005

Noobtube 

A technical error on YouTube, hindering viewing pleasure.

*The playback of a fully loaded YouTube video stops abruptly*
You: "NOOBTUBE!"

Noobtube by WaterproofTowel August 14, 2010