1. Without question
   "they hired unimpeachably first-rate faculty members"
   - unquestionably

See also: unimpeachable

• diphtheritic
• diphthong
• diphthongal
• diphthongise
• diphthongize
• Diphylla
• Diphylla ecaudata
• Dipladenia
• Dipladenia boliviensis
• Diplazium pycnocarpon
• diplegia
• diplo-
• diplococcus
• Diplococcus pneumoniae
• diplodocus
• diploic vein
• diploid
• diploidy
• diploma
• diplomacy
• diplomat
• diplomate
• diplomatic
• diplomatic bag
• diplomatic building