taskmaster
/ˈtɑːskmɑːstə(r) ˈटास्क्मास्ट(र्)/ noun [C] a person who gives other people work to do, often work that is difficult दूसरों से प्राय: कठिन काम करवानेवाला, ख़ूब काम करानेवाला या वाली अधिकारी
She was a hard taskmaster.