The Collaborative International Dictionary of English v.0.48:

Serviceable \Serv"ice*a*ble\, a.
   1. Doing service; promoting happiness, interest, advantage,
      or any good; useful to any end; adapted to any good end
      use; beneficial; advantageous. "Serviceable to religion
      and learning". --Atterbury. "Serviceable tools."
      --Macaulay.
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            I know thee well, a serviceable villain. --Shak.
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   2. Prepared for rendering service; capable of, or fit for,
      the performance of duty; hence, active; diligent.
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            Courteous he was, lowly, and servysable. --Chaucer.
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            Bright-hearnessed angels sit in order serviceable.
                                                  --Milton.
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            Seeing her so sweet and serviceable.  --Tennnyson.
      [1913 Webster] -- Serv"ice*a*ble*ness, n. --
      Serv"ice*a*bly, adv.
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WordNet (r) 3.0 (2006):

serviceableness
    n 1: the quality of being able to provide good service [syn:
         serviceability, serviceableness, usableness,
         useableness, usability]