twenty-something (or twentysomething) is a term used for people at the age of 20 to 29. its is used instead of "twentyfive years old" for example, because at this age its harder to tell how old someone is (by looking at him/her) than it is in the teenage years (and often it "matters" less).
dude #1: how old is Tim?
dude #2: I don't know.. he is a twenty-something, thats for sure
dude #1: thank you for this exact piece of information
by SgrDD March 11, 2008
A specific demographic group, those aged 20-29. Often Obama supporters (regardless of the country they live in), heavy drinkers, users of urbandictionary.com (and the souce of all the worthwhile-to-read definitions, as opposed to the adolescents that write the unfunny definitions that either profess their love for a gf/bf or proclaim their hatred of a schoolmate), students, servers, bartenders, clubgoers, in massive debt yet still optimistic, and believe that they can change the world if they just work together (until they reach the threshold age of 30, when 98% people realize the futility of their causes).
The author of this UD definition belongs to twenty-somethings demographic.

The courageous protesters at Tiananmen Square were mostly twenty-somethings.
by Leroy Brown 420 February 4, 2009
Twenty something
Special pricing for anyone aged twenty something
by Cttar January 18, 2019
The Twenty-Something Condition(TSC) is the phase in a person's life spanning the years from 20 to 29. It is marked by an immense sense of confusion and inner turmoil, with emotions springing between the extreme ends of the spectrum. Persons with TSC do not wish to change the past(see quarter life crisis), instead focusing more on second-guessing their choices for the future. They rarely plan for more than a few months in advance; a long term goals lasts one year. The question 'what do I want' plagues their lives.

Symptoms of this condition include but are not limited to:
Unexplained laughter/tears. Poor nutrition and health habits. Heightened sense of pressure. Job hopping. Questionable financial decisions. Emotional breakdowns. Jealousy of other people's lives. Over-thinking to the point of not thinking at all. Unintended Sobriety/Drunkenness. Fear of commitment. Procrastination.

As of yet there is no known cure, but studies have shown that identifying with other victims can mitigate symptoms. If you think you or anyone you know might have the Twenty-Something Condition please feel free to shout TSC in solidarity.
Henry: "All these weddings are making me broke."
Heather: "Welcome to the twenty-something condition"

"I think Jess has a bad case of the twenty-something condition. Yesterday she broke down into tears over a Cheerios commercial and then went back to watching the game like nothing happened."

Farah: "I feel like I'm breaking up with my dreams."
Laurel: "TSC, friend. TSC"

Jed:"Will you need a roommate in a few months?"
Kyle: "Hell if I know, I've got the twenty-something condition. Who knows where I'll be."

Tess: "I told him I was still a student so I didn't have to explain my whole list of odd jobs over the last few months."
Jake: "Makes sense. I get it. TSC."
by sleepingbooty September 23, 2012