Dense

1. Having relatively high density.Synonym: solid
2. Compact; crowded together.Synonyms: compact, crowded, packed; compactAntonyms: diffuse
3. Thick; difficult to penetrate. Synonyms: thick, solidAntonym: thin
4. Opaque; allowing little light to pass through.Synonyms: cloudy, opaque; opaqueAntonyms: clear, diaphanous, see-through, translucent, transparent
5. Obscure, or difficult to understand.Synonyms: abstruse, difficult, hard, incomprehensible, obscure, toughAntonyms: clear, comprehensible, easy, simple, straightforward, understandable
6. (mathematics, topology) Being a subset of a topological space that approximates the space well. See Wikipedia article on dense sets for mathematical definition.Antonym: meager
7. (of a person) Slow to comprehend; of low intelligence.Synonyms: dumb, slow, stupid, thickAntonyms: bright, canny, intelligent, quick, quick-witted, smart; intelligent

Antonyms

• (crowded together): diffuse, few and far between (of things as opposed to one thing), scattered, sparse, rarefied (scientific, to describe gases)