If you describe something as marginal, you mean that it is small or not very important.
This is a marginal improvement on October.
这是在10月份的基础上作出的小小的改进。
The role of the opposition party proved marginal.
反对党的作用被证明是微不足道的。
If you describe people as marginal, you mean that they are not involved in the main events or developments in society because they are poor or have no power.
The tribunals were established for the well-integrated members of society and not for marginal individuals.
这个特别法庭是为社会中的主流人群设立的,而不是为了无足轻重的小人物。
I don't want to call him marginal, but he's not a major character.
我不会说他只是个无足轻重的小角色,但他也不是重要人物。
Marginal activities, costs, or taxes are not the main part of a business or an economic system, but often make the difference between its success or failure, and are therefore important to control.
The analysts applaud the cuts in marginal businesses, but insist the company must make deeper sacrifices.
分析家们赞同对边际业务的削减,但坚持认为公司必须作出更大牺牲。