A good theologian will need a philosophy of definition. This philosophy will guide how they use words and the choices as to how they define words. A good philosophy of definition will make the goal for the use of words to be communication, rather than persuasion and certainly never deception.
Even so, theology has a lot of specialized word usage which can muddy the waters of communication. Every field of study does. This type of specialized definition is necessary when the depth of inquiry requires very specific and subtle, differences in similar concepts. This type of very specific definition to words that otherwise have broader meanings requires the careful clarification of the speaker to be sure the hearer understands.
Using definitions of words which purposefully mislead the hearer is a form of dishonesty. This is pretty obvious for most people, but for others it is a point of opportunity. One of the unfortunate developments in theology is people defining common terms, historically well-defined terms, and giving them a new meaning as a means of proclaiming their new ideas to be in line with traditional concepts. This redefinition may be a means of gaining acceptance, or it may be an attempt to change the hearer’s perception of truth.
The situation is much like a scene I saw in a comedy sketch. A man asks a woman to marry him. She excitedly agrees. Then when she tries to set up the wedding he explains he had a more minimalistic definition of a wedding. His definition didn’t include a public ceremony, flowers, dress, reception, legal document, or commitment. But it did include a honeymoon, he pitched in hopefully. Of course, the young lady was less than agreeable to this redefinition.
Charles W. Short 