If anyone considers himself religious and yet does not keep a tight rein on his tongue, he deceives himself and his religion is worthless.
Religious comes from a word that means to cry out. It is definitely referring to worship, and it is talking about crying out to God. If you consider yourself a worshiper, and one who is calling on the name of the Lord, you must rein your tongue in.
The word religion is similar to the word for religious, but it refers more to the outward ceremonies. There is nothing wrong with ceremonies in the Church, by the way. Without digging too much into this topic, it matters less what the ceremony is, and more your heart in the ceremony.
If you are doing all of the right stuff in church, or during your times of worship, whether community or personal, but you can't even watch your mouth... its pointless worship. Don't kid yourself (and be deceived) God is not fooled at all. As the psalmist puts it, "it is a broken spirit, a broken and contrite heart that God desires."