Synonyms for Affair (same or very similar meaning)
WordNet sense 1 (a usually secretive or illicit sexual relationship):
amour, intimacy, involvement, liaison, affaire
WordNet sense 2 (a vaguely specified social event):
function, occasion, social function, social occasion
WordNet sense 3 (a vaguely specified concern):
matter, thing
From the ODE community, based on WordNet
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