onerousness

onerous +‎ -ness

onerousness (countable and uncountable, plural onerousnesses)

1. The state or characteristic of being onerous.
   • 1898, McKinley, Second State of the Union Address:

     The Government of Greece strongly urges the onerousness of the duty here imposed upon the currants of that country, amounting to 100 per cent or more of their market value.

• burdensomeness, onerosity