- Resistant to pressure.
- Requiring a lot of effort to do or understand
adverb (harder, hardest)
- a hard problem
- Demanding a lot of effort to endure.
- a hard life
- (context, of a person) , severe, harsh, unfriendly, brutal.
- hard evidence
- Of drink, strong.
- Of water, high in dissolved calcium compounds.
- (context, slang, vulgar) Sexually aroused.
- (bodybuilding) Having muscles that are tightened as a result of intense, regular exercise.
- With much strength or energy
- The central part, usually cylindrical, of a wheel; the nave
- A point where many routes meet and traffic is distributed, dispensed or diverted
- Hongkong airport is one of the most important air traffic hubs in Asia.
- (computers) a computer networking device connecting several ethernet ports. See switch.
- (surveying) A stake with a nail in it, used to mark a temporary point.