This is a Kenyan slang sheng borrowed from the Swahili language meaning nothing matters more than life. It is commonly used when things don't work out as planned or expected.
In some cases, it's used to as a polite way of telling somebody to mind their business.
Short-hand for the word floccinaucinihilipilification, meaning the estimation of something as valueless (encountered mainly as an example of one of the longest words in the English language).
Precedes or follows either a gratuitously disrespectful or honest remark, originated in New York City. Used in similar fashion to "no offense" or "to be honest," interchangeably.
Ya mans is wild buns, respectfully. Respectfully he's washed.
After school, The Modells on Jamaica Ave was active. Respectfully.