The term "swearing" is currently used to cover a broad swath of objectionable speech. Here are some categories:
Scriptural injunctions against swearing oaths exist. Exodus 20:7 (KJV) provides the scriptural backing for not taking the name of the Lord (and, by extension, other religious figure) in vain, and this was clearly taken seriously by the Hebrews, who went so far in the way of avoiding the use of the Lord's name, that the pronunciation of the word Jehova, as the ancient Hebrews would have rendered it, is extremely uncertain. It has pointed out by a number of sources, that there are issues with the translation that muddy our ability to understand what was intended by Exodus 20:7. The suggestion has been made that the intended meaning of the passage is that we are not to act as false representatives of God in committing evil. (Essentially, what would often be referred to as "antichrist".) As the passage implies that the sin being described might not be forgivable, this interpretation seems to make the passage seem more coherent.