underdeliver
Definitions
To fail to provide the amount, quality, or level of service that was promised or expected.
To produce results that fall short of a previously stated goal or commitment.
Examples
The marketing agency promised a massive increase in traffic but continued to underdeliver on their key performance indicators.
It is better to underpromise and overdeliver than to set unrealistic expectations and consistently underdeliver to your clients.
Synonyms
fall short underperform fail to meet expectations come up short miss the mark
Antonyms
overdeliver exceed expectations surpass goals outperform go above and beyond