What is gha'it (feces), what is madhiy (pre-seminal fluid), and what is wadiy (post-urination discharge)? May Allah benefit you.

Feces are what exits from the anus. Madhī (pre-seminal fluid) is a thin, sticky fluid that exits during minor arousal, and necessitates washing the male organ and performing wuḍūʾ (ablution). Wadī (post-urination fluid) is a thick, white fluid that usually exits after urination. All three of these are impure.