duple

coupled dual duplex duplicate geminate paired twin twofold

as much again binary binate dualistic twice two times

singular

single

bifold binal binary coupled double doubleheader duplex duplicate matched paired twin

corresponding duplex equal equivalent same twin

alike carbon-copy dualistic identic identical indistinguishable self-same tantamount twofold very same

different dissimilar mismatched unequal unlike variable

unmatching

bifold binal binary diploid double dual duplex duplicate paired