It is when you believe in something

You may believe 100% in it or less

That something you believe affects your life in some shape or form

That affect is seen by others

The stronger the faith, the more visible the affect is

If no one sees the affect, then the faith is very weak or is no longer there

One is a hypocrite if they believe in a faith yet they don't apply any of it's wisdom

Or their faith has evolved into some other

For example, If your faith says to help your neighbor and your neighbor doesn't need help, then it's ok.  But if you know that your neighbor needs help and you are capable then you are not faithful

It is possible to be unfaithful temporarly and be faithful again

That is what is called a sin of your faith.  The faith was on hold while you are doing something against it

We all have a faith.  We all sin.

The best among us, are the ones who regret their sins

It feels much better once we regret what we have done

The best faith is the one that is most adaptable to all of us and addresses our needs and wants