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.
I noticed that too. What an old biddy.
"is that biddy wearing uggs in the summer?"
However, "biddy" in this sense might have died a welcome death had it not been for the influx of Irish immigrants into the U.S. in the early 19th century. Young Irish women often had their passage paid by upper-class American families, for whom they would then work as domestic servants while they paid off their debt. The practice was so widespread that such women came to be known as "Biddies," from a shortening of "Bridget," a common Irish women's name. This use of "biddie" reinvigorated the word, and ever since it has been employed by insolent children to torment their elders.
Sometime in the last 20 years or so, the term was recycled to mean a woman of any age. The connotation may exemplify the earliest expression synonymous with the concept now known as MILF.
"I'm trying to pick up a biddy"