residuary

noun
  1. 1

    One who receives the residue of an estate.

adjective
  1. 1

    Of or relating to a residue; residual; left over, when the main portion has been removed.

  2. 2

    With respect to a will, relating to the portion of an estate which was not disposed of in the will, or for which the directions in the will could not be carried out.

Source: https://en.wiktionary.org/wiki/residuary