An acronym that ask a question when you're extremely frustrated and don't have time to text all 18 characters . It consists the add in of two letters "y" and "m" to the popular acronym "wtf" meaning
The source of mansplaining, men over explain things because women use why questions to complain or moan about the way things are based on their observations and criticisms of their surroundings.
Wife: "Why are your underwear on the floor?"
Husband: "Stop whymoaning, either pick them up, or tell me to pick them up and I will! Unless you do of course want me to mansplain the sport of laundryball"