heavy 普通用词，指重量或体积大大超过同类物体，常用作引申，多指精神上的重压等。
weighty 多指实际上而不是相对的沉重，引申指严重或重要。
参考例句
1. Heavy overcast sky, I feel very depressed, as I feel. 天空阴沉沉的，感觉很压抑，一如我的心情。
2. The Heavy Gauss Cannon is more effective at penetrating vehicle armor. 重的高斯大炮是更效果的在敏锐的车辆装甲。
3. The road went over hills and plateaus, through heavy forests and grasslands. 走过去的道路丘陵和高原，通过大量的森林和草原。
英英解释
n.
1. an actor who plays villainous roles
2. a serious (or tragic) role in a play adj.
1. of comparatively great physical weight or density
2. unusually great in degree or quantity or number
3. of the military or industry; using (or being) the heaviest and most powerful armaments or weapons or
4. marked by great psychological weight; weighted down especially with sadness or troubles or weariness
5. usually describes a large person who is fat but has a large frame to carry it
6. (used of soil) compact and fine-grained
7. darkened by clouds
8. of great intensity or power or force
9. (physics, chemistry) being or containing an isotope with greater than average atomic mass or weight
10. (of an actor or role) being or playing the villain
11. permitting little if any light to pass through because of denseness of matter
12. of relatively large extent and density
13. made of fabric having considerable thickness
14. prodigious
15. full and loud and deep
16. given to excessive indulgence of bodily appetites especially for intoxicating liquors
17. of great gravity or crucial import; requiring serious thought
18. slow and laborious because of weight
19. large and powerful; especially designed for heavy loads or rough work
20. dense or inadequately leavened and hence likely to cause distress in the alimentary canal
21. sharply inclined
22. full of; bearing great weight
23. requiring or showing effort
24. characterized by toilsome effort to the point of exhaustion; especially physical effort
25. lacking lightness or liveliness
26. (of sleep) deep and complete
27. in an advanced stage of pregnancy adv.
1. slowly as if burdened by much weight
