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

• teaspoonful
• teat
• teatime
• teazel
• teazle
• Tebaldi
• Tebet
• tebibit
• tebibyte
• tec
• tech
• techie
• technetium
• technic
• technical
• technical analysis
• conservator-ward relation
• conservatory
• conserve
• conserved
• conserves
• consider
• considerable
• considerably
• considerate