What's the meaning of "I gotta take a shit!"?

The phrase "I gotta take a shit!" is a vulgar slang expression meaning "I need to defecate" or "I need to go to the bathroom to have a bowel movement." It is often used informally and can be considered offensive in formal or polite contexts. Similar expressions include "take a crap," "take a dump," and "take a squat," with "take a shit" being the most offensive among them13.