A bible-basher is a Christian who holds very tightly to what the Bible says and tries hard to make other people accept it too. The word is not kind. People use it when they feel pushed, preached at, or unable to get away from the message. It is informal, and more British than American; Americans often say bible-thumper for the same idea. You would not use it for a quiet person who simply goes to church. It marks someone who will not leave the Bible out of the conversation and who wants you to come along. Though actually, the “bash” is not usually about slamming a real book on a table. It is the feeling that the person is beating you with verses. Because the word shows disapproval, it can sound like an insult if you point it at someone in the room.