The act of defecation, where the person has been waiting for a long time and the result is an inordinately large and powerful session on the crapper. It could possibly break the bowl.

a poop so big that it makes a thunderous sound. People who take a thunder dump, or TD, tend to feel a splash of water on their butts afterwards.

A violent bowel movement, usually loose, which the person may have been storing for some time due to lack of access to ammenities. Propelled by a buildup of gas caused by the fact that a fart during this time would have resulted in a follow through.

It is characterised by shitting out your entire lower colon (and, possibly, a kidney or two) in the space of 2 to 3 seconds.

The result leaves the thunderdumper feeling up to half a stone lighter, noticeably weak, but relieved.

to give shock knowledge to someone, to shock them with your information, to enlighten them with new information