say it: uhn-HAP-ee-nis
unhappiness is a noun meaning "emotions experienced when not in a state of well-being". It carries 2 recorded senses.
emotions experienced when not in a state of well-being
state characterized by emotions ranging from mild discontentment to deep grief
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 unhappiness 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.