In the novel "Things Fall Apart" what do the terms Agadi-nwayi and Agbala tell us about women in Ibo society?

In Things Fall Apart, the Igbo use epithets
which show one's status in the tribe.  Among them are:

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agadi-nwayi:  old
woman

agbala:  woman; also used of a man who
has taken no title

efulefu:  worthless
man

osu:
 outcast

So, the hierarchy is set up
for men, obviously.  Men are judged by the accumulation of titles and worth (number of children,
wives, cowries, heads).  A man who does not have any children, wives, cowries, or heads is simply
"worthless," but a man who takes no titles is considered beyond worthless, so weak that he is not
a man at all; instead, he is a woman.

Women are not judged by the
titles or worth.  They must attach themselves to a man in order to attain status.  Then, they are
given a number: first wife, second wife, third wife--a chain of command.  Their status is only
secured by marriage.  Within marriage, their goal is to provide male
children.

Women are also given status if they have survived to be
old.  With high mortality rates for children and mothers, an old woman would be given respect for
her contribution to the tribe in terms of fertility and matriarchy (having and raising many
healthy children).

More, women are only give supreme status if they
have some kind of religious or supernatural power, like Chielo, the priestess of Agbala, or
powerful war medicine, agadi-nwayi, a magic used by the spirit of an old
woman with one leg to achieve peace instead of war.  Many surrounding villages fear the tribe
because their priestess and medicine men are so powerful.