Such a funny word sleuth. Makes me think of board games and long ago novels. It conjures up old busybodies and peering through magnifying glasses to find clues in the days before tech took over.
The word itself is very old and found in Old Norse, meaning a track or trail. In Scotland, from the 14th century, a sleuthhound was a bloodhound. It hunted game or tracked down fugitives from justice.
Then in the nineteenth century, sleuthhound was used for a detective and shortened to sleuth. (etymology found through Merriam Webster)
But in the world of cozy mystery. the amateur detective is more often young, running her own business, and reliant on a female confidante.
The only thing she has in common with the detectives in past series is often the lack of ready cash.
And, of course, the threat she faces to her own way of life, if she does not investigate the crime and unmask the criminal.