“Afzakkertje” generally stands for one last drink. Translation depends on context, see 1. and 2.
The verb “afzakken” literally translates to “to come/slide down”, so “een afzakkertje” would be “a little downslider”… 🙂
1. One for the road [noun] [het afzakkertje, de afzakkertjes] [‘af-zak-kur-tju’]
This translation is used in the context of having one last drink before leaving.
– “Jongens, zullen we nog een afzakkertje doen in de Pijpela?”
(“Fellows/guys, shall we have one for the road in the Pijpela?” You can also say “een afzakkertje nemen”. The “Pijpela” is the only bar in the Hague that is open till late. And to many of you that might still not be late, but it is a whole lot better than the usual 1.30 AM!)
2. Nightcap [noun] [het afzakkertje, de afzakkertjes] [‘af-zak-kur-tju’]
This translation is used in the context of having one last drink before going to bed.
– “Liefie, wil je nog een afzakkertje voordat we naar bed gaan?”
(“Sweetie, would you like to have a nightcap before we go to bed?”)
– “Drankje”: drink.
– “Neut”: drink, slam, drop.
– “Afzakken”: to come/slide down.