What is the proper name of lips between hips?

There isn't a "proper name" for the area between the hips. It's commonly referred to as the groin or inguinal region.

Here's why there isn't a specific term for that area:

* Anatomically: The area between the hips is not a distinct anatomical structure. It's part of the lower abdomen, encompassing parts of the pelvis and upper thighs.

* Functionally: The area between the hips doesn't serve a single function. It houses several important structures like blood vessels, lymph nodes, and nerves.

It's important to be mindful of the language we use when referring to this region, as some terms can be considered offensive or inappropriate.