underbound

verb2

1. •
   To specify or use boundaries that are too small; to have boundaries that do not encompass the entirety of an entity.

   • The corporate limits of a city, therefore, offer a political definition that commonly underbounds the geographic extent of the urban area. — 1978
2. •
   To provide a lower bound to.

   • It will be seen that our computation time underbounds his; and that, in fact, we can give a group for which the difference in computation time is arbitrarily large. — 1968