say it: i-LOO-siv-nuhs
elusiveness is a noun meaning "the quality of being difficult to grasp or pin down". It carries one recorded sense.
the quality of being difficult to grasp or pin down
“the author's elusiveness may at times be construed as evasiveness”
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 elusiveness come from Princeton University’s WordNet. The pronunciation comes from the CMU Pronouncing Dictionary. Commonness is measured against a corpus of everyday English. Full sources and licences.