beer belly [noun] [de bierbuik, de bierbuiken]

"Bierbuik" is the Dutch word for "beer belly". It’s definitely not a
nice thing to say that someone has a beer belly. "Buik" is used in many
other ways (see DWOTD "Buik") and the Dutch even use it as part of a verb (see "Extra").

Examples:
– "Als je zo doorgaat met bier drinken heb je op je 30e een bierbuik!"
("If you continue drinking beer like that you’ll have beer belly when you’re 30!" Note that in Dutch the word "beer" translates to "bear".)

– "Ondanks zijn bierbuik is het hem gelukt de marathon van New York uit te lopen!"
("Despite his beer belly, he managed to finish the New York marathon!")

– "Hij gaat elke week naar de sportschool om zijn bierbuik weg te krijgen, hij traint net zolang tot hij een wasbordje heeft."
("He goes to the gym every week to get rid of his beer belly, he will
train until he has six pack abs." Please note that "wasbordje"
literally means "washboard", the board that was used by your
grandmother to wash clothes on.)

Related words: 
– "Buikspreker": ventriloquist [noun] [de buikspreker, de buiksprekers].
– "Buikpijn": stomachache [noun] [de buikpijn, no plural].
– "Buikje": little belly [noun] [het buikje, de buikjes].
– "Uitbuiken": digest your food comfortably [verb] [uitbuikte, uitgebuikt].

Extra:
When you sit back and relax after a lavish dinner, this is called
"uitbuiken" in Dutch. Literally, it means something like "to stomach
out", or give your stomach some room. Typically, people who are in the
event of "uitbuiken" will stretch their legs and lean backwards on the
couch or a chair to give their stomach some space.

Example:
– "Pff, ik heb zoveel gegeten, even uitbuiken!"
("Pff, I ate so much, let’s sit back and relax!")