Final answer:
A synonym for 'sterling' is 'superb' or 'exemplary', indicating high quality, while an antonym is 'inferior' or 'substandard', indicating poor quality.
Step-by-step explanation:
The word sterling has multiple meanings, but it is most commonly used to describe something that is of excellent or superior quality.
A synonym for sterling when used in this context could be superb or exemplary, which also convey the idea of something being of high quality or exceptional. On the other hand, an antonym for sterling could be inferior or substandard, signifying something that fails to meet an accepted level of quality.
Usually, in an educational setting, sterling would be used to describe high-quality work or performance, such as a sterling essay or a sterling academic record.