"hungry" describes the condition where one craves intake of more food. what is the English name for the condition where one needs to expel the end result?
There is no common word that describes this condition. American English speakers will politely say:
I need to go to the bathroom.
British English speakers may say something like:
I need to go to the loo.
I need to visit the WC.
None of these are explicit about what kind of waste is being eliminated, but in polite company you don't usually need to be exact about your toilet activities.
There are a wide variety of less polite alternatives, which I started to try to list, but gave up.
Fecal urgency is the term for really needing to go.
Prairie dogging, as depicted in the movie Rat Race (2001):
Kimberly Pear: [Kimberly needs to go to the bathroom] Dad, I'm prairie dogging it! Randy Pear: What the hell does that mean? Jason Pear: You know, like when a prairie dog sticks his head in and out of the ground. Randy Pear: Oh. [Five seconds later] Bev Pear: Ugh! Randy Pear: Ohh, god, I do not wanna picture that!