Definify.com

Webster 1913 Edition

(dĭl′ly̆)

Noun.

[Contr. fr.

diligence

A kind of stagecoach.

“The Derby dilly.”

J. H. Frere.

dilly ‎(comparative more dilly, superlative most dilly)

dilly ‎(plural dillies)

Someone or something that is remarkable or unusual.
- Raymond Chandler, Playback
  You're the most impossible man I ever met. And I've met some dillies.

Contracted from diligence.

dilly ‎(plural dillies)

(dated) A kind of stagecoach.
- J. H. Frere
  So, down thy hill, romantic Ashbourn, glides
  The Derby dilly, carrying six insides.