Oof

Oof, a death sound originating from Messiah (or Roblox if you do not like nostalgia) is also used as a word to describe getting hurt, getting surprised, or getting dismayed. People do not actually know how it is pronounced; it might be 'oooh-ph' or 'ooh-uh-f' or 'oo-fh'. Either way, people find humor is this word because is sounds like a 6-12 year old guy getting hurt by another 6-12 year old guy.

Example 1:
Person 1: *kicks Person 2*
Person 2: Oof!

Oof is also used as an acronym, standing for 'Out of Office'. This basically means some office guy takes a leave for some reason. Here is an example....

Person 1: Im gonna go for your birthday party tommorow!
Person 2: But dont forget to take an OOF before you leave.
Person 1: Oh yeah! I would have forgottten for sure.

Facts:
Synonyms: Ouch, Ow, Ugh
Acronyms: (Sorry, I could not find a useful acronym.)
Oof, because it is humorous, is also used as a meme.

Oof! why did you hurt me?