undersize

/AH1 N D ER0 S AY0 Z/
adjective
  1. 1

    Smaller than normal, undersized.

    โ€œThis isn't a pony, it's just an undersize horse.โ€

  2. 2

    Smaller than appropriate, expected or sufficient.

  3. 3

    Small enough to fit through a screen.

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