a.

1. 硬的，坚固的
   The ice is as hard as rock.

   冰像石头一样硬。

2. 困难的，费力的[+to-v]
   George is hard to get along with.

   乔治很难相处。

3. 猛力的；辛苦的
   He gave the door a hard kick.

   他猛力踢门。

4. 刻苦的；努力的[B]
   She is a hard worker.

   她是一个工作十分勤奋的人。

5. 艰难的；难受的
   I know that he has a very hard life.

   我知道他日子过得很艰难。

6. 冷酷无情的；严厉的；严格的[（+on）]
   She is too hard on her pupils.

   她对学生太严格了。

7. （气候）酷寒的
   It was a hard winter.

   那是一个严寒的冬天。

8. 【语】发硬音的（如c, g念成[k][g]）
9. （水）硬质的
10. （毒品）毒性强的，使成瘾的[B]
11. 确实的；不容怀疑的[B]
    We confronted him with hard facts.

    我们把铁的事实摆在他的面前。

12. 【军】设重防的；（导弹发射场或导弹）设于地下可免受敌方空袭的

ad.

1. 努力地；艰苦地
   She tried hard, but failed.

   她努力尝试过，但未能成功。

2. 猛烈地；重重地
   It's raining hard.

   雨下得很大。

3. 困难地；困苦地
   The old man is breathing hard.

   这位老人呼吸困难。

4. 牢固地，紧紧地
   He held hard on to the rope.

   他牢牢抓着绳子。

5. 接近地；立即地
   One misfortune followed hard on another.

   不幸接踵而来。

adj.

1. solid, firm, and rigid; not easily broken, bent, or pierced.
   ▸(of a person) not showing any signs of weakness; tough.
2. requiring or demonstrating a great deal of endurance or effort; difficult.
   ▸strict and demanding:

   a hard taskmaster.
   ▸denoting an extreme or dogmatic faction within a political party:

   the hard left.
3. (of information or a subject of study) concerned with precise and verifiable facts:
   hard science.
4. harsh or unpleasant to the senses.
   ▸(of a season or the weather) severe.
5. done with a great deal of force or strength:
   a hard whack.
6. strongly alcoholic; denoting a spirit rather than beer or wine.
   ▸(of a drug) potent and addictive.
7. (of water) containing mineral salts.
8. (of pornography) highly obscene and explicit.
9. (of prices of shares, commodities, etc.) high and stable; firm.
10. (of radiation) highly penetrating.
11. (of a consonant) pronounced as a velar plosive (as c in cat, g in go).

adv.

1. with a great deal of effort.
   ▸with a great deal of force; violently.
2. so as to be solid or firm.
3. to the fullest extent possible:
   put the wheel hard over to starboard.

n.