forgetful

/F AO0 R G EH1 T F AH0 L/
adjective
  1. 1

    Unable to remember things well; liable to forget.

  2. 2

    Dropping some of the input's structure or properties before producing an output.

    โ€œa forgetful mapping; a forgetful functorโ€

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