1. 一流的;极好的;最优的
If you describe something or someone as first-class, you mean that they are extremely good and of the highest quality.

2. 甲级的;一等的;优等的
You use first-class to describe something that is in the group that is considered to be of the highest standard.

3. (车厢、船舱、机舱)头等的，一等的
First-class accommodation on a train, aeroplane, or ship is the best and most expensive type of accommodation.

4. (英)优先投递的，第一类的;(美)第一类邮件的(适用于信函和明信片)
In Britain, first-class postage is the quicker and more expensive type of postage. In the United States, first-class postage is the type of postage that is used for sending letters and postcards.

1. very good
f the highest quality

e.g. made an excellent speech
the school has excellent teachers
a first-class mind

Synonym: excellentfantabuloussplendid