taxing
adj.adj. describing something that is very tiring and needs a lot of mental or physical effort.
adj. requiring a significant amount of physical or mental effort; demanding or burdensome. Often used to describe tasks, schedules, or intellectual challenges.
The long climb up the mountain was very taxing.
After a taxing day at the office, she usually prefers a quiet evening at home to recover her energy.
The professor warned that the final exam would be particularly taxing, requiring students to synthesize complex theories from the entire semester under a strict time limit.
Compare typologically Russian мыта́рство (mytárstvo) (< мы́тарь (mýtarʹ, “publican (tax collector)”)).
Typically follows a linking verb like 'be', 'become', or 'find', or precedes the noun it modifies.