Furthermore is a transitional adverb used to add more information or arguments to what has already been said.
Common synonyms include: moreover, in addition, besides, what's more.
Example sentences:
1. The project is too expensive; furthermore, it's not feasible with our current resources.
2. She's qualified for the job. Furthermore, she has relevant experience.
3. The apartment is spacious and bright. Furthermore, it's located in a prime area.