One who gourmandizes; a person who eats excessively or feasts greedily.
From gourmandize plus the agent noun suffix '-er'. This creates a noun describing the person who performs the action of gourmandizing.
English's '-er' suffix is so powerful that you can attach it to almost any verb to create 'the person who does that thing'—a gourmandizer is literally 'one who gourmandizes,' showing English's elegant word-building system.
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