1. Causing fear or dread or terror
   "a career or vengeance so direful that London was shocked"
   - awful, dire, dread, dreaded, dreadful, fearful, fearsome, frightening, horrendous, horrific, terrible

See also: alarming, direfully

• immunodeficient
• immunoelectrophoresis
• immunofluorescence
• immunogen
• immunogenic
• immunogenicity
• immunoglobulin
• immunoglobulin A
• immunoglobulin D
• immunoglobulin E
• immunoglobulin G
• immunoglobulin M
• immunohistochemistry
• immunologic
• immunologic response
• immunological
• immunological disorder
• immunologically
• immunologist
• immunology
• immunopathology
• immunosuppressant
• immunosuppressed
• immunosuppression
• immunosuppressive