Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
fluidness is a noun meaning "the property of flowing easily". It carries 2 recorded senses.
the property of flowing easily
“adding lead makes the alloy easier to cast because the melting point is reduced and the fluidity is increased”
“they believe that fluidity increases as the water gets warmer”
a changeable quality
“a charming Oriental fluidity of manner”
“a certain fluidness in his perception of time made him an unpredictable colleague”
“demographers try to predict social fluidity”
Forms marked · are formed by the regular rule rather than recorded in the source data. English keeps a few hundred irregulars and the rest follow the pattern, so the rule is right far more often than not — but it is a rule, and the mark says so.
Definitions, synonyms and semantic relations for fluidness come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.