Source : WordNet®

let down
     v 1: move something or somebody to a lower position; "take down
          the vase from the shelf" [syn: {lower}, {take down}, {get
          down}, {bring down}] [ant: {raise}]
     2: fail to meet the hopes or expectations of; "Her boyfriend
        let her down when he did not propose marriage" [syn: {disappoint}]