(1)実質または重要性の欠如
(2)重要性または重点を欠いた
(3)濃くない
(4)not dense; "a thin beard"; "trees were sparse"
さらに詳しく
(1)住人の数が減った状況(または住人が全くいない)
(2)the condition of having reduced numbers of inhabitants (or no inhabitants at all)