Historical clue formulations

• Just between us — 2026-09-29
• Hush-hush — 2025-08-26
• Hush-hush — 2019-08-20
• Hush-hush, slangily — 2018-11-05
• Discreetly, informally — 2018-10-08
• Out of action, in baseball lingo — 2015-10-25
• Hush-hush — 2015-10-14
• Injured, in baseball lingo — 2007-09-16
• Out of action, in baseball lingo — 2006-09-01