underinsurance

noun | \ ˌən-dər-in-ˈshu̇r-əns \ | un·der·in·sur·ance
  1. : insufficient insurance

  1. : insurance coverage protecting usually against uninsured or underinsured motorists by compensating the insured if the tortfeasor's liability policy limits fall short of the insured's losses : insurance providing uninsured motorist coverage