What does "tendentiousness" mean?

The characteristic of being tendentious.

Tendentiousness

Common synonyms include: advocacy bias, bias, partiality, partisan framing, prejudice, rhetorical bias.

noun

noun ·Rare ·Advanced level

Noun

1
The characteristic of being tendentious. uncountable, usually
"Near-synonyms: partisanship, bias, biasedness, slant, partiality, prejudice"
2
an intentional and controversial bias wordnet

"Near-synonyms: partisanship, bias, biasedness, slant, partiality, prejudice"

From tendentious + -ness.