Final answer:
An antonym for the word sparse is 'abundant' or 'plentiful', while a synonym for sparse would be 'scarce' or 'meager', indicating something that is not dense or is in small amounts.
Step-by-step explanation:
The antonym and synonym for the word sparse are quite straightforward. An antonym is a word that has the opposite meaning to another word, whereas a synonym is a word that has a similar meaning.
For the word sparse, which means thinly scattered or in small numbers, a common antonym would be abundant or plentiful, indicating a large or rich supply. A synonym for sparse would be scarce or meager, which also convey the idea of being few in number or quantity.