| 2026-01-25 | Private investigator, informally |
| 2025-08-15 | P.I. |
| 2025-04-15 | Private eye, in old crime novels |
| 2024-12-26 | Gumshoe |
| 2024-05-22 | Private eye, in old slang |
| 2023-12-06 | Hercule Poirot, e.g., for short |
| 2022-05-09 | Private eye, in old slang |
| 2021-11-20 | Gumshoe |
| 2021-08-09 | Private eye, quaintly |
| 2021-08-03 | Private eye, in old lingo |
| 2020-06-06 | Shamus |
| 2019-05-24 | Sam Spade, e.g., informally |
| 2019-05-20 | Sleuth, in slang |
| 2018-11-16 | Solver with a set of clues, for short |
| 2018-04-15 | Private eye |
| 2018-03-26 | Investigator, in old film noir |
| 2018-01-25 | P.I. |
| 2017-10-18 | Private eye, in old slang |
| 2014-12-01 | Sleuth, in old crime fiction |
| 2014-05-24 | Classic Bogart role, in slang |
| 2014-02-14 | 20-Across, e.g., informally |
| 2013-09-18 | Private investigator, in old slang |
| 2013-09-10 | Sleuth, in slang |
| 2013-06-02 | Sleuth, in slang |
| 2013-03-31 | Sam Spade, e.g., for short |
| 2012-10-13 | P.I. |
| 2012-10-07 | Gumshoe |
| 2012-09-19 | Sleuth, informally |
| 2012-07-22 | Private eye |
| 2012-04-08 | Private investigator, in slang |
| 2011-08-31 | Gumshoe |
| 2011-04-02 | Sue Grafton's Kinsey Millhone, e.g. |
| 2011-01-10 | Sleuth, in slang |
| 2010-12-03 | Spade, e.g., for short |
| 2010-10-17 | Shamus |
| 2010-10-14 | Gumshoe |
| 2010-10-12 | Private eye |
| 2010-06-01 | Gumshoe |
| 2010-02-19 | Sherlock |
| 2010-01-31 | Private eye |
| 2010-01-17 | Spade, e.g., for short |
| 2009-12-23 | Sam Spade type |
| 2009-10-09 | Sherlock |
| 2009-09-29 | Sleuth, slangily |
| 2009-09-23 | Gumshoe |
| 2009-07-26 | Gumshoe |
| 2008-09-18 | Dick |
| 2008-08-26 | Sleuth, informally |
| 2007-12-18 | Private eye, for short |
| 2007-07-31 | Private eye, slangily |
| 2007-07-29 | P.I. |
| 2007-05-22 | Private eye, slangily |
| 2005-09-13 | Gumshoe |
| 2005-06-15 | Private eye |
| 2005-04-24 | Person with a magnifying glass, for short? |
| 2004-09-11 | Shamus |
| 2003-11-26 | Clue hunter, informally |
| 2003-08-29 | Case studier, slangily |
| 2003-07-26 | Dick |
| 2003-05-15 | Gumshoe |
| 2003-04-22 | Investigator, slangily |
| 2002-02-16 | Clue collector, slangily |
| 2001-10-11 | Sleuth, for short |
| 2001-01-28 | P.I., e.g. |
| 2000-12-02 | Pinkerton, e.g. |
| 1999-06-13 | Dick |
| 1998-11-24 | Private eye, for short |
| 1998-04-29 | P.I. |
| 1998-01-05 | Sleuth, informally |
| 1997-12-14 | Shamus |
| 1997-05-18 | Private eye |
| 1997-01-27 | Gumshoe |
| 1996-04-07 | Mike Hammer, for one |
| 1995-06-09 | Dick |
| 1994-09-19 | Old-time gumshoe |
| 1994-09-06 | Gumshoe |
| 1994-07-17 | Lt. Columbo, e.g. |
| 1994-04-16 | Dick |
| 1994-01-31 | Gumshoe |