m/w can be often spotted in a bio, typically on discord or twitter with a name or @ usually followed after. it stands for "matching with" which indicates the context between a pfp to show who has the other half of the picture.
Person 1: Hey, what's your pfp?
Person 2: Oh, I'm just m/w my friend John. He wanted to match profile pictures so I agreed.
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.