impermissibly
1. [ adverb ] not permissibly
Examples:

"the radon level in the basement was impermissibly high"

Related terms: permissibly impermissible impermissible
Similar spelling:   impermissible
  impermissibility
  impermeability
  imperceptibly
  impermeable
  imperishable
  improperness
  imperialistic
  imperceptible
  impersonally
  impersonal
  impermeableness
  imperialist
  imperialism
  imperatively