What does "prolonged mental inventory" mean? [closed]

Solution 1:

With the additional context you provide, I can break down the full meaning for you.

First of all, "taking inventory" means to make a list with a count of all the relevant items. (For example, normally when a store "takes inventory", they go through the entire store and count all of their saleable stock so they know exactly what they have or need.)
To take a "mental inventory" is to do the same thing, but entirely in your head: you don't write it down, you just make sure to remember it.
To take a "prolonged mental inventory" is to take an unexpectedly long time performing your mental inventory.

The full context makes it apparent that the "imposingly attired lady" has been staring at Miss Hope long enough to make her uncomfortable, studying and examining her appearance as if attempting to memorize everything about her; and then the lady speaks to her in a very firm, authoritative manner, as if there is no possibility that she could be mistaken.

Solution 2:

An inventory is a list of all the items in a particular location or set of locations. Although usually used for a list of all the items held in stock by a company you can also make an inventory of the objects in your home, office, your luggage or hotel room, or even about your person.

Most inventories are recorded on paper or an electronic system. If someone were to memorise all the items of a given inventory instead of writing them dowm or storing them using a piece of software they would have prepared a 'mental inventory'.

If that someone were to make a very careful and complete mental inventory it would take much longer than a more superficial one. It would, therefore, be a 'Prolonged Mental Inventory'.

The person referred to is subjecting her (probably carefully crafted) image of herself to a Prolonged Mental Inventory process.

Solution 3:

In this case it would mean that she was taking a long, long time inspecting her clothes (in the closet) and her appearance (in the mirror).

Prolonged: longer than usual and/or necessary; protracted in time; lengthy.

Mental: as opposed to physical. The inventory was taking place in her head only. She wasn't actually writing anything down.

Inventory: the aggregate value of a stock of goods.