not with a bang but a whimper

not with a bang but with a whimper

In an anti-climactic way. Typically used to describe the end of something. The phrase is taken from the last stanza of T.S. Eliot's poem "The Hollow Men": "This is the way the world ends / Not with a bang but a whimper." We all thought the championship was going to be a close game, but it ended up being a blowout, and the season ended not with a bang but with a whimper.
See also: bang, but, not, whimper
Farlex Dictionary of Idioms.

not with a bang but a whimper

LITERARY
If something happens not with a bang but a whimper, it is less effective or exciting than people expected or intended. The Cannes film festival approached its climax yesterday not with a bang but a whimper, as thousands of disappointed festival-goers left early. Note: You can also say that something happened with a bang and not a whimper to mean the opposite. Should the monarchy go, it would be with a memorable bang and not a whimper. Note: This is the last line of T.S. Eliot's poem `The Hollow Men' (1925): `This is the way the world ends Not with a bang but a whimper.'
See also: bang, but, not, whimper
Collins COBUILD Idioms Dictionary, 3rd ed.
See also:
  • not with a bang but with a whimper
  • whimper
  • stanza
  • a thing of beauty is a joy forever
  • commit (something) to memory
  • commit to memory
  • name and shame
  • hollow out
  • at length
  • end (something) on a high note
References in periodicals archive
Rage, rage against the dying of the light." But what the Globe writer had in his head was Thomas Stearns Eliot's "Hollow Men," and its droning close: "This is the way the world ends / This is the way the world ends / This is the way the world ends / Not with a bang but a whimper."