Jengkol is a large bean like seed from a Javanese forest tree (Archidendrum pauciflorum)
Its is to culinary tastes what i guess garlic is to the west. Some love it, some hate it, many love it but still avoid it due to its effects on breath and body odour.
Jengkol is the stinky food, the stinky addictive food ;)
The jengkol tree is a forest tree in the legume family, it is cultivated widely on Java and some other islands as well as scattered throughout Asia as far as Burma.
The edible portion is the large seed, like a bean, inside the pod fruits.
Jengkol contains a toxin called jengkolic acid