German for 'shit' and like in English, is a vulgarity. It can be used as an exclamation and a synonym for feces.
The verb 'To shit (deficate)' is Scheißen.
The soft E on the end is often dropped in common conversation or in times of emergancy but is seldom used by English speaking people and they may assume you're mispronouncing it.
Ich muss scheissen, entschudigung. (I have to shit, excuse me.)
Scheiss! Es ist defekt. (Shit! It's busted.)
Person 2: scheiße!