introvert, worrier Iconspeaker_3
[de bin-nen-vet-ter, de bin-nen-vet-ters]

Binnenvetter A "binnenvetter" is somebody who is not only an introvert, but also worries too much by not sharing the things that bother him with others and keeping most feelings to him/herself. The adverb "binnen" means "within, inside". The word "vetter" is not really used independently, but "vet" in this context most likely means "fat", which is something you also build up on the inside 🙂

The English noun "introvert" best translates in Dutch as "een in zichzelf gekeerd persoon".

A related verb you may hear is "opkroppen": to bottle up (feelings, anger, etc.).

– "Ben jij een extravert type?" – "Nee, ik ben meer introvert. Eigenlijk ben ik een binnenvetter." 
("Are you the outgoing type?" – "No, I'm rather introverted. I'm actually a real worrier.")

– "Sander is een echte binnenvetter. Hij kropt zijn gevoelens op en ondervindt daar later de nadelige gevolgen van." 
("Sander is a real worrier. He bottles up his feelings and later suffers the (adverse) consequences.")

– "Ik heb altijd geleerd om alles zelf op te lossen. Misschien ben ik daarom een binnenvetter." 
("I have always learned to solve / deal with everything myself. Perhaps that's the reason I'm introverted.")

– "Maak van je hart geen moordkuil!": do not disguise your feelings, speak up your mind, be frank!

– "Wees toch niet zo'n binnenvetter, maak van je hart geen moordkuil! Vertel me wat er aan de hand is!"
("Don't be such an introvert! Be frank about your feelings! Tell me what's wrong!")

Related words:
– Introvert: introverted [adjective].
– Opkroppen: to bottle up, to pen up, to hold back [verb] [kropte op, opgekropt].

– "Hij heeft altijd zijn woede opgekropt en nu is dat tot een uitbarsting gekomen!"
("He has always bottled up his anger and now this has led to an outburst!")

– Gevoelens: feelings [noun, plural] [het gevoel, de gevoelens].
– Zorgen: worries [noun, plural] [de zorg, de zorgen].
Piekeren: to worry, to brood [verb] [piekerde, gepiekerd].