underdeliver

under- +‎ deliver

underdeliver (third-person singular simple present underdelivers, present participle underdelivering, simple past and past participle underdelivered)

1. To deliver less, or at an inferior level, than promised or expected
   • 2009 March 3, “Promoters fake Howard support”, in Herald Sun‎:

     […] the result was a warning to all exhibition organisers about the dangers of overpromising and underdelivering when promoting events.

   • 2022 October 5, “Network News: Private sector's role in a publicly-owned railway”, in RAIL, number 967, page 16:

     "[...] If the economy has tanked... then we don't want to over-promise and under-deliver."

• underdelivery