bloodhound
n. countablen. a large dog with a very strong sense of smell, often used to find people or things. It can also describe a person who is very determined to find the truth or to catch someone.
n. a large breed of dog with a powerful sense of smell, historically used for tracking. By extension, it refers to a person who is relentless in their pursuit of information or justice.
The police used a bloodhound to find the missing hiker.
The journalist acted as a bloodhound, following every lead until he finally uncovered the truth about the company.
While the literal bloodhound is valued for its olfactory prowess, the metaphorical sense describes an investigator who refuses to let a trail go cold, no matter how long the search takes.
Inherited from Middle English blodhound, blodhond; equivalent to blood + hound. Cognate with Dutch bloedhond (“bloodhound”), Middle Low German blōthunt (“bloodhound”), German Bluthund (“bloodhound”), Danish blodhund (“bloodhound”), Swedish blodhund (“bloodhound”). The detective sense follows from the dog's ability to follow a trail.