unproductive

/AH0 N P R AH0 D AH1 K T IH0 V/
adjective
  1. 1

    Not productive; useless; fruitless.

    โ€œJuggling is an amusing pastime, but generally unproductive.โ€

  2. 2

    (of affixes, mechanisms of word formation, etc) No longer used to produce new words ().

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