In the UK an Organ Grinder refers to someone who in charge or very important.
The UK uses the saying Organ Grinder to refer to a person who is in charge, rather than a lackey or representative.
The Dictionary defines "organ grinder's monkey" as "one who acts for or does the bidding of someone much more powerful."
It further defines it below: If you call someone the organ grinder's monkey, you mean that they are doing what a powerful person wants them to do, but have no real power themselves.
Some ways to use organ grinder in a sentence are.
We want the organ grinder not the monkey. After all, in a sense he is the organ grinder.
I shall give way to the organ grinder in a moment.
The organ grinder has wisely stayed hidden away in a room.
Organ Grinder can also mean someone who plays an organ.