This is the 1461st most frequent Russian word.
командир
Commander.
In this sentence, 'командир' refers specifically to a military officer who commands a unit.
Командир приказал начать атаку.
The commander ordered to start the attack.
Here, 'командир' is used metaphorically to represent someone leading a group, not necessarily in a military context.
Он всегда был хорошим командиром команды.
He has always been a good leader of the team.
In this instance, 'командир' denotes the person appointed to take charge of a specific activity or event.