1. Inspiring fear
   "a tougher and more redoubtable adversary than the heel-clicking, jackbooted fanatic"
   - formidable, unnerving, doubtable [archaic] 
2. Worthy of respect or honour
   "born of a redoubtable family"

See also: alarming, reputable

• ketchup bottle
• keteleeria
• ketembilla
• ketembilla tree
• ketoacidosis
• ketoacidosis-prone diabetes
• ketoacidosis-resistant diabetes
• ketoacidosis-resistant diabetes mellitus
• ketoaciduria
• ketohexose
• ketone
• ketone body
• ketone group
• ketonemia
• ketonic
• ketonuria
• ketoprofen
• ketorolac
• ketorolac tromethamine
• ketose
• ketosis
• ketosis-prone diabetes
• ketosis-resistant diabetes
• ketosis-resistant diabetes mellitus
• ketosteroid