Historical clue formulations

• Adjective that becomes its own synonym after its first letter is dropped — 2026-09-04
• Most diabolical — 2024-08-15
• Closest to base? — 2018-01-14
• Most baleful — 2016-11-11
• Least good — 2002-07-07
• Most vicious — 2001-03-17
• Most wicked — 1999-04-26