Fundament
Part of speech: noun
Definition: foundation The part of the body upon which one sits; the buttocks; specifically, the anus. underlying basis or principle for a theoretical or mathematical system
Arse
Part of speech: noun
Definition: (not used in US, Canada) buttocks; the back of anything.(not used in US, Canada) stupid, mean or despicable person.
Part of speech: verb
Definition: To be silly, act stupid or mess around.To have the effort to do something, to be bothered.
Example sentence: I need them, need them to give me a kick up the arse. Otherwise I'd just be sat-in getting fat, counting me money. It's good people living on your doorstep and looking through your bins. Gives you energy.