which when referring to a person means expecting a lot of work or attention from others, or not easily satisfied.
My boss is very demanding, he makes us work a lot.
My grandma became very demanding when she got older.
You can also use this adjective to refer to things such as a piece of work, meaning that this work needs a lot of skill or effort.
This is the most demanding challenged I've ever faced.
I'm exhausted because my job is very demanding.