A person who bellies or crawls on their belly; someone or something with a large or prominent belly.
From 'belly' plus the agent suffix '-er' (one who does or has something). An archaic or informal formation following English word-building patterns.
This is an obscure word that probably survives only in specific regional or occupational contexts—like how coal miners might have used 'bellyer' for someone who crawled through tight mine shafts.
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