Definition of "setter"

In this sample, twenty of the twenty-seven fire setters received a primary or secondary diagnosis of conduct disorder, compared with only eleven of twenty-seven nonsetters.

2000, Rita Wicks-Nelson, Allen C. Israel, Behavior Disorders of Childhood, page 188

One of the most admired and best-known crossword setters in the English language, Graham was known for his idiosyncratic style and extended anagrams.

2013 November 26, John Plunkett, “Rev John Graham, aka crossword setter Araucaria, dies aged 92”, in The Guardian‎

The two Gordon setters came obediently to heel. Sir Oswald Feiling winced as he turned to go home. He had felt a warning twinge of lumbago.

1931, Francis Beeding, “7/2”, in The Norwich Victims‎

It was desperately close until all but the closing moments, and for that we had the 32nd-ranked [Julien] Benneteau to thank for bringing the fight out in [Roger] Federer, whose thirst for these long battles has waned over the past couple of years. For a player regarded by many as the greatest of all time his record in completed five-setters is ordinary: now 20 wins, 16 losses.

2012 June 29, Kevin Mitchell, “Roger Federer back from Wimbledon 2012 brink to beat Julien Benneteau”, in The Guardian‎, archived from the original on 15 November 2016

O, 'tis our setter. I know his voice

c. 1597 (date written), William Shakespeare, “The First Part of Henry the Fourth, […]”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, [Act II, scene ii]