outwardness has 1 distinct synonym spread across 1 of its 3 senses. Each sense below keeps its own list, because a synonym belongs to a meaning and not to a word: swapping one sense's substitute into another sense's sentence is how a thesaurus makes writing worse. Its one recorded opposite is inwardness.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
concern with outward things or material objects as opposed to the mind and spirit
“what is the origin of the outwardness of our sensations of sound, smell, or taste”
the quality or state of being outside or directed toward or relating to the outside or exterior
“the outwardness of the world”
Synonyms, antonyms and the broader and narrower relations for outwardness come from Princeton University’s WordNet. Full sources and licences.
a concern with or responsiveness to outward things (especially material objects as opposed to ideal concepts)
“hearty showmanship and all-round outwardness”