Is alley a old french word?

No, "alley" is not an Old French word. It has its origins in Old English, where it was spelled "æl" and meant "a narrow path or lane." It eventually evolved into the modern "alley" through Middle English.

The word "alley" is ultimately derived from the Proto-Germanic word "alīz", which also meant "a narrow path or lane."

So, while "alley" does have a long history, it's not connected to Old French.