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A friend without a partner who gets in the way and prevents couples from having the necessary time to socialize in private. Severe cases of third wheeling can cause major relationship problems for the couple they have attached to. A relationship parasite that feeds off your good intentions and destroys the host. Vampires that wear a smile and offer to 'help' but eventually turn out to have an agenda. Anybody happy to third wheel long term will usually turn out to be a bad friend.
will arrange nights out with one or other partner individually. generally refuses to recognise boundaries like giving a couple space, not constantly invading their home/life. Gets jealous or nasty when told to back off. causes trouble between couples but in a quiet way. Usually tries to make themselves necessary by doing the chores expected of either partner ie picking kids up from school, driving people around. The more they do the harder to remove them it will be. Third wheels are generally frowned upon, with good reason.
by Father O'Connell December 24, 2013
It's like a schematic of 3 wheels about the moment socialization:

-Third Wheel: biggest one, which consist in a group of people whom are you fond of, but not being very intimate.

-Second Wheel: small and inside the Third Wheel. People that is priority of your attention.

-First Wheel: smaller and inside the Second Wheel. Consists in something/yourself (or both) that is automatically a main concern.
Usually, for the majority of these wheels are like this:

-Situation: going out with friends/family and bf(gf).

Third Wheel: your friends/family

Second Wheel: your bf(gf)

First Wheel: yourself/your beliefs/your pride/your ego

-Situation: going out with friends.

Third Wheel: most of your friends

Second Wheel: your best friend

First Wheel: yourself/your beliefs/your pride/your ego
by Azfargh September 19, 2012
A person who can ruin a weekend, picnic, concert, sporting event, or any other kind of activity that you may have planned with your significant other by inviting themselves or guilting you into inviting them. These people are commonly refereed to as a Third Wheel. Third Wheeling is not cool and is frowned upon.
Dude! She's such a Third Wheel, I cant believe she tried to go to prom with them.
by Boogie44 September 29, 2010
When in a group of three there is always the one that doesnt fit in. We consitter him/her as the "3rd wheel" because they just dont fit. If there is a couple together and then one of there cousins, it just doesnt make since for the cousin to be there. If there are two caucasian people standing with a black man, the black man is obvously the "3rd wheel". Two Catholics and a Jew, Two Canadians and a Mexican, and so on
Ryan: jordan, what the hell are you doing with us?

Jordan: shit, i feel like the third wheel
by Ryan Gerstner March 14, 2005