1. Not capable of being improved on
   - unexcelled, unexceeded

See also: best

• dictostylium
• dictum
• Dictyophera
• Dictyoptera
• dictyopteran
• dictyopterous insect
• dictyosome
• dicumarol
• dicynodont
• Dicynodontia
• didactic
• didactical
• didactically
• didacticism
• didactics
• didanosine
• didder
• diddle
• diddler
• diddley
• diddly
• diddlyshit
• diddlysquat
• diddums
• Didelphidae