The Collaborative International Dictionary of English v.0.48:

Sleuthhound \Sleuth"hound`\, n. [See Sleuth, and cf.
   Slothound.] (Zool.)
   A hound that tracks animals by the scent; specifically, a
   bloodhound. [Spelt variously slouthhound, sluthhound,
   etc.]
   [1913 Webster]

WordNet (r) 3.0 (2006):

sleuthhound
    n 1: a detective who follows a trail [syn: sleuth,
         sleuthhound]
    2: a breed of large powerful hound of European origin having
       very acute smell and used in tracking [syn: bloodhound,
       sleuthhound]