It's the "alone" part which is inserted from outside: it's an erroneous addition.
Even the word "complete" does not mean exhaustive or "sola." It means it's one of the things you need to make yourself complete.
By way of analogy, if I have a fully-provisioned backpack of supplies for a hike, and I have a canteen of water too, the water may be "profitable" and may make me "complete" but I still don't proceed on water ALONE: I believe in "aqua" but not in "Aqua Sola."
That has to be about one of the worst analogies I’ve read on these threads.
The Catholic definition of *sola* is severley wanting.
Catholics tend to argue from their own distorted opinion of what WE mean when we say *Sola Scriptura*, which Catholics refuse to accept.
Now Catholics tend to get all bent of of shape and huffy when they think we are defining their terms for them, and yet have no problem defining OUR terms for us. Rules for thee but not for me.
That’s known to the rest of the world as *hypocrisy*.