Pharisees refers to people belonging to the "Pharisee sect," one of the major sects of Judaism during Jesus' time.
At that time, the three largest sects in Israel were the Pharisees, Sadducees, and Essenes. They were known for strictly observing the Law of Moses and the rules that were developed as an extension of that Law.
They believed in resurrection and angels.
They placed such great importance on strictly observing the established law that they could not tolerate Jesus' actions, which violated their "written law." As a result, they not only participated in bringing Jesus to his death but also remained a force that constantly hindered the disciples' evangelism thereafter.