Many fields, such as science and law, use specialised terms. People within the field will usually understand those terms, so you can include them in material for that audience. Doing so helps to retain the credibility and accuracy of your writing. For the right audience, specialist terms convey a lot of information succinctly.
However, think about whether your document will be read just by people in the field, or whether it will also have a more general audience. If your document may have a wider audience, limit the number of specialised terms used, and include a simple definition of each one if you do use them.
See General and specialised audiences for further discussion on ways to deal with general and specialised audiences.