There's no special word just for doing that with passwords that I know of.

However, the term for when you just do something physical like that without thinking about it is "muscle memory". Another example is working a combination lock you've been using for a long time, but not being able to actually tell another person what the combination is (without grabbing hold of the lock and working it and reciting the numbers as you get to them).

The problem of course is if the thing you've trained your body to do changes (eg: your combination changes), then the muscle memory actually works against you. At least until you can retrain.

There's no special word just for doing that with passwords that I know of.

However, the term for when you just do something physical like that without thinking about it because you done it a jillion times before is "muscle memory". Another example is working a combination lock you've been using for a long time, but not being able to actually tell another person what the combination is (without grabbing hold of the lock and working it and reciting the numbers as you get to them).

The problem of course is if the thing you've trained your body to do changes (eg: your combination changes), then the muscle memory actually works against you. At least until you can retrain.