overpromise

• over-promise

over- +‎ promise

overpromise (third-person singular simple present overpromises, present participle overpromising, simple past and past participle overpromised)

1. To promise more than is delivered.

   Synonym: overcommit

   We don't want to overpromise.

   • 2008 December 6, Tiyana Grulovic, “Brows are a gal's best accessory”, in Globe and Mail‎:

     So rather than posh skin creams that overpromise, a good brow job gives instant results.

   • 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."

• oversell
• write checks one can't cash