Sparse

The most appropriate antonym of the word sparse is abundant.

• Sparse means "having few or widely spaced parts or members."
• Abundant means "present in large quantities; plentiful."

The other words do not have the same meaning as "sparse" and are therefore not antonyms.

• Scant means "not enough or barely sufficient."
• Confident means "having or showing confidence or assurance."
• Spared means "not harmed or injured."