I'm sure BranShea will be able to help as she speaks Dutch.

On the etymology side of things: Dutch gezellig 'cozy, comfy' is related to German Gesell 'companion, fellow' and derives from the Germanic root *sal whence German Saal 'hall' (also English salon, saloon via Italian, cf. English comrade, German Kamrad, from Latin camera 'room', also French chambre, German Kammer and English home and homey both the noun and the adjective). German Gesellschaft 'association', gesellen 'to join (something)'.

Ceci n'est pas un seing.