This is the 429th most frequent Persian word.
مسئول
Responsible.
Here, 'مسئول' functions as a noun meaning 'responsible person' or 'leader' of a group.
او مسئول گروه کاری است.
He is responsible for the work group.
In this sentence, 'مسئول' is used as an adjective describing a state of responsibility.
من خود را مسئول این اشتباه میدانم.
I consider myself responsible for this mistake.
Here, 'مسئول' is part of a state or condition, referring to the quality of being responsible.