This is the 2109th most frequent Russian word.
руководитель
Leader; manager; supervisor.
Here, 'руководитель' is used to denote a leader or manager in a formal organizational context.
Руководитель компании принимает важные решения.
The head of the company makes important decisions.
In this context, 'руководитель' refers to a supervisor or a person who guides and supports a group.
Наш новый руководитель очень помогает в обучении команды.
Our new manager is very helpful in training the team.
Here, 'руководитель' is used to describe a specific role leading a particular project.