scarcest

/S K EH1 R S AH0 S T/
adjective
  1. 1

    Uncommon, rare; difficult to find; insufficient to meet a demand.

  2. 2

    Scantily supplied (with); deficient (in); used with of.

Source: https://en.wiktionary.org/wiki/scarce, https://en.wiktionary.org/wiki/scarcest