The phrase "wardrobe necessity" refers to an item of clothing or accessory that is essential or very important to have in one's wardrobe. Full definition
A basic wardrobe necessity, this long sleeve t - shirt dress is complete with a shift construction, front pocket, and finished off with a V shaped neckline. (sophieandtrey.com)
Ah the leather jacket is one of the ultimate wardrobe necessities. (the-habit.com)
If you live in a cold weather state, black velvet pants are a great wardrobe necessity! (stylesidebar.com)