Ladette

From OUP online:

ladette (also less frequent laddette) /lædet/ noun (BrE, informal)

a young woman who behaves in a confident and noisy way, and who drinks alcohol and enjoys sport or other activities that are traditionally enjoyed by men: 17-year-old Zola and her gang of ladettes boast about just how much under-age drinking they did last weekend.* He says that young women today may look at someone like Sophia Loren and admire the way she looks, but they aspire more to being sexy, pretty or a ladette. * She has also had a reputation as a hard-drinking, hard-partying ladette who seems to enjoy the single life. * Analysts believe the ladette phenomenon has been driven by increasing levels of financial independence among young women.

Ladette comes from the word lad, which originally meant a boy or young man. In Britain in recent years, lad has been used more often to describe a lively young man who is interested in drinking, sports and meeting women: All my other mates said he was a bit of a lad, always making trouble. Robert has a reputation as a bit of a lad. He dates lots of women and flirts with any attractive female. Young men have their range of lad mags (= magazines for young men), but what magazine is a man over 40 supposed to buy exactly? Boys who don’t fit in with the ‘lad culture’ feel left out and often get bullied at school, according to a 2001 survey.

The -ette ending has been added to make the feminine form.

Other derivatives include:

• laddish (adjective): Traditional laddish behaviour is generally a sign of
  insecurity and immaturity. His quick wit and likeable brand of laddish humour make him the perfect chat-show guest.
• laddishness (noun): Behind all the laddishness, he is rather a sensitive young man.
• laddism (noun): Beginning as a journalistic pigeon-hole for boisterously
  anti-social young men, laddism has since been extended to include anyone under 40 behaving badly.

A lad can be contrasted with a new man, a man who is more sensitive and not aggressive, and who shares the work traditionally done by women in the home, such as cooking and taking care of children: He is comfortable with his ‘new man’ image, and has been known to leave the office early to go home and cook dinner for his family.