资料来源 : pyDict

必要的,必不可少的;实质上

资料来源 : WordNet®

of the essence
     adj : of the greatest importance; "the all-important subject of
           disarmament"; "crucial information"; "in chess cool
           nerves are of the essence" [syn: {all-important(a)}, {all
           important(p)}, {crucial}, {essential}, {of the
           essence(p)}]