adjective / noun / interjection
tough
TUF/tʌf/
Difficult to break down or overcome.
Pushing the loaded wheelbarrow up the steep slope is a tough task.

Etymology
Originally describing material that held firm and resisted separation, the word extended to things hard to endure. That resistance underlies the modern sense of a task or situation requiring sustained effort.
In context
it was a tough week but the weeks are only going to get even more difficult
More examples
- The steak is too tough to chew comfortably.
- Choosing between the two job offers is a tough decision.
- Two neighborhood toughs threaten the shop owner.
- “If you don't like the rules, tough,” the coach says.
Forms
tough · tougher · toughest · toughs
toughness noun — The ability to withstand damage or hardship.
toughen verb — To make or become more resistant.