Grizabella is a worn out older cat, with a shabby greyish fur.
It's said that she was really beautiful when she was young, and
she was loved by the other cats (kind of like Victoria is now).
She left the tribe to see the world but ended up seeing more than
she expected, seeing trough human eyes you can say that she saw
more of the world of prostitutes and such.
And when she decides to return to the jellicles she is shunned of
by them.
Especially the queen's don' t want to have anything to do with
her, because of her past.
And especially Jellylorum, Jennyanydots and Skimbleshanks becomes
very protecting over the kittens, and won't let them near
Grizabella, in an attempt to save their innocence.
But because of their innocence the kittens see her for who she is,
not for how she lived.
The second time she approaches the other cats they leave, and
deeply saddened by the other cats hatred she sing out her story,
not aware of that Deuteronomy is still there watching and hearing
her. And when she begins to leave she for a moment thinks she
feels someone reaching out to her, but no, it must have been her
imagination. She walks away.
It's not until after Grizabella sings Memory the other cats
understand what she has gone through and finally accept her.