Keeper n. : One who, or that which, keeps; one who, or that which, holds or has possession of anything.

Keeper n. : One who retains in custody; one who has the care of a prison and the charge of prisoners.

Keeper n. : One who has the care, custody, or superintendence of anything; as, the keeper of a park, a pound, of sheep, of a gate, etc. ; the keeper of attached property; hence, one who saves from harm; a defender; a preserver.

Keeper n. : One who remains or keeps in a place or position.

Keeper n. : A ring, strap, clamp, or any device for holding an object in place; as: (a) The box on a door jamb into which the bolt of a lock protrudes, when shot. (b) A ring serving to keep another ring on the finger. (c) A loop near the buckle of a strap to receive the end of the strap.

Keeper n. : A fruit that keeps well; as, the Roxbury Russet is a good keeper.

Example:
What do you hate about fantasy football Keeper leagues?

Taxonomy
Keeper, Moon Cup, menstrual cup, women, The Moon, mooncup, latex, gum rubber, natural gum, grade silicone, menstruation period, medical-grade, allergy, feminine hygiene products, Home Office, Headquarters, environment-friendly, non-latex.

Defination from the web:
KEEPER and THE MOON CUP are small internally worn, reusable menstrual cup, made from natural gum rubber or silicone. ... Simple to use, both The Moon Cup and The Keeper are innovative feminine hygiene products that are worn internally, freeing women from dependency ...