double circle (indicating "very good" on a piece of school work)
dual personality; split personality
twofold and threefold; doubled and redoubled
dual structure; double structure
instrumental duet; instrumental duo
double helix (structure of DNA)
double-glazed window; double window; storm window
someone with a dual personality
double star; visual double
double torture; double pain; double hardship; double whammy
dual nationality; dual citizenship
double weave; double cloth
redundant keigo (i.e. improper use of the -rareru honorific form together with an honorific verb such as ossharu)
double standard of morality
dual attachment concentrator
issuing (the same receipt) twice; issuing duplicate (receipts)