say it: KLUHM-zee-nuhs
clumsiness is a noun meaning "unskillfulness resulting from a lack of training". It carries 3 recorded senses.
unskillfulness resulting from a lack of training
the carriage of someone whose movements and posture are ungainly or inelegant
the inelegance of someone stiff and unrelaxed (as by embarrassment)
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 clumsiness 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.