The feminine form of vieille is vieille itself. This is because vieille is already the feminine form of the adjective vieux, which means "old".
The word vieille is used for feminine singular nouns, while vieux is used for masculine singular nouns.
For example:
- La vieille femme (The old woman)
- Le vieux monsieur (The old man)
The plural form of vieille is vieilles, and the plural form of vieux is vieux.
