A glutton is someone who eats far more than they need, often in a greedy or excessive way. Picture someone at a buffet piling their plate so high that food spills over the edges, then going back for seconds and thirds even though they're already full. That's gluttonous behavior.

While everyone occasionally eats too much at Thanksgiving dinner or a birthday party, a glutton makes a habit of it, eating not because they're hungry but simply because the food is there.

The word has expanded beyond food. When someone is a glutton for punishment, they keep doing something difficult or unpleasant even when they could stop. A student who signs up for three hard classes, joins two sports teams, and volunteers every weekend might be called a glutton for punishment. The phrase suggests they're willingly taking on more hardship than necessary, almost as if they're consuming difficulty the way a glutton consumes food.

Gluttony is the related noun, and it's traditionally been considered one of the seven deadly sins in Christian teaching, grouped with vices like greed and pride. The concern isn't about enjoying good food but about a lack of self-control and the selfishness of taking more than your share.