TWITs stands for 'Teenage Women in Their Thirties' and refers to 30-something women who have extended their adolescence, as well as those who, after starting a family, have entered a second teenage lifestage. The poster girls might be Pink, Victoria Beckham and Gwen Stefani.
As noted by Australian social researcher Mark McCrindle (www.mccrindle.com.au), the popularisation of lifestyle segments began in the 1980’s most notably with the Yuppies (Young Urban Professionals) and then the DINKs (Double Income, No Kids). The 1990’s introduced us to the SNAGs (Sensitive New Age Guy) and the WAGs (Wives And Girlfriends –notably of sporting stars). Other recent labels include KIPPERS (Kids In Parents' Pockets Eroding Retirement Savings), NETTELs (Not Enough Time To Enjoy Life), the Downagers, the Silver Stylers and the Boomerang kids.

A Twitter user

An insult formed from the combination of the words 'twat' and 'clit'.

a person who is addicted to twitter.

Noun. A regular user of twitter, a web site and service that allows people to post short text messages. The label is not necessarily pejorative.

twit (noun)

a foolish person

synonyms: nerd, geek, dork, dweeb, schmuck, putz, goober, plonker, prat, wally

The scientific term for a pregnant goldfish