demanding
UK: dɪˈmɑːndɪŋ | US: dɪˈmændɪŋ
adj. requiring much effort, skill, or attention
adj. (of a person) expecting others to meet high standards
The word "demanding" originates from the verb "demand," which entered Middle English from Old French demander (to request), itself derived from Latin demandare ("to entrust, command"). The Latin roots are de- (thoroughly) + mandare (to order). Over time, "demand" evolved to imply insistent requests, and the suffix -ing transformed it into an adjective describing something (or someone) that persistently requires effort or compliance.
The job is physically demanding, requiring long hours of labor.
She is a demanding teacher but prepares her students exceptionally well.
The software has demanding system requirements.
His demanding attitude often strains relationships.
Climbing Mount Everest is one of the most demanding challenges in the world.