1. 极好的;非常棒的;了不起的
    If you describe something or someone as terrific, you are very pleased with them or very impressed by them.

    e.g. What a terrific idea!...
           多么好的主意！
    e.g. Everybody there was having a terrific time...
           在场的每个人都玩得开心极了。

2. 很多的;很大的;很强的
    Terrific means very great in amount, degree, or intensity.

terrific的反义词

    e.g. He did a terrific amount of fundraising...
           他做了大量的筹款工作。
    e.g. All of a sudden there was a terrific bang and a flash of smoke.
           突然传来惊天动地一声响，还冒出一股烟。