seemliness
The property of being seemly, appropriateness of conduct or behavior.
uncountable
Her black dress, simple to austerity, suggested her bereaved condition, and I was innocently astonished that notwithstanding a real emotion she was able to dress the part she had to play according to her notions of seemliness.
The result or product of being seemly.
countable
Where it comes from
From Middle English semelynes, semlynesse, equivalent to seemly + -ness.
Adapted from the Wiktionary entry seemliness (CC BY-SA 4.0).