There's a good many reasons why people should follow it.

Why is there an 'a' before 'good many reasons'?

  • 1
    It is an idiomatic expression: dictionary.cambridge.org/it/dizionario/inglese/good-many
    – user 66974
    Aug 7, 2022 at 7:33
  • 1
    Have you looked in any dictionaries? Many include the phrase "a good many". (If you are looking for its etymology, then please clarify.) Also, that phrase is usually construed as plural. Aug 7, 2022 at 8:35
  • I am not convinced that the singular usage is common. Can you quote sources?
    – Anton
    Aug 7, 2022 at 10:49
  • 1
    It's bad grammar. Not the "a", but "is". It should be "There are a good many reasons why people should follow it."
    – Hot Licks
    Aug 7, 2022 at 12:06
  • @Anton A few possible ʀᴇᴀꜱᴏɴꜱ ᴅᴏ exist for using the nominally singular indefinite article a/an with quantified plural nouns without this having any effect at all on their inherently plural grammatical number for verb agreement purposes, and some of these are explored in answers to the selected duplicates that lot of ᴘᴇᴏᴘʟᴇ ᴀʀᴇ investigating even now as we speak. :)
    – tchrist
    Aug 7, 2022 at 14:36