Synonyms for Formidable

Synonyms starting with letter I

• impressive

  difficult, majestic
• intimidating

  participle, horrible, difficult
• imposing

  horrible
• indomitable

  impressive, difficult
• impregnable

  dreadful, horrible
• immense

  enormous, huge
• influential
• important
• incredible
• intricate
• invincible

  impressive
• irksome
• intense

  difficult
• irritating
• ill-tempered
• implacable
• involved
• ignoble
• infamous
• inexorable
• intractable
• inconceivable
• inexplicable
• intolerable
• impending
• insecure
• icky
• industrious
• intensive
• illustrious
• imminent
• inspiring
• impactful
• infestive
• in control
• in the saddle
• inclement
• intemperate
• irritable
• irascible