A "biddy" is one of those girls who wears very short skirts and very high heels in very cold weather, and walk around downtown areas on their way to parties where they're going to get smashed and act like hoes, and then make the walk of shame back to thieir dorms in the same heels and short skirts the next morning.

A European dialect word for 'Chicken or Hen', but was originally a word/sound used when 'calling chickens (i.e. biddybiddybiddy).

It's quite uncommon to hear it now, but it's an old (mostly British colloquialism) to refer to old women (of a certain disposition) as 'birds' or 'hens'.

Subsequently, the term 'Biddy' became a term used to refer to an old women, generally one who is fussy or garrulous.

An old woman who gets in the way or is just annoying (sometimes shortened to bid)

When a hot or attractive woman is around you or your friends and you do not want to go out and say in front of her to your buddy HEY LOOK A HOT GIRL! simply say biddy and a direction and thus everyone knows

The way people who think they're cool refer to hot women.

In the UK usually preceded by the word old to denote a generally annoying old woman getting in the way or ruining your fun. The origin comes from the word Libido or sex drive