SIO 

senior investigating officer

a british police rank rank held by a police officer (DCI at minimum), who leads a major investigation (e.g.:murder)

Who is the SIO of this murder taskforce? It's DCI Peter Banks.
Who's in charge of this murder investigation? DCI Harold Crowly is the SIO. Talk to him.

SIO by UltraDan September 25, 2020

sio 

Extreme sexy beastly mf

Man, Sio gives off such a big dick, dilf energy!

sio by txmmmm November 21, 2021

Sio 

A tall handsome long dicked man who often steals the wives of other men by just looking

Keep Sio away from my girl he’s always piping her down

Sio by anonymous November 23, 2021

SIO 

Sex in Opposition: the (non)-act of (non)-sex between two or more people. SIO is typified in musical form by songs such as News from Babel's "Dragon at the Core" and Domestic Stories' "The Same River"

I've got the latest order from ReR in! Let's put on the Necks and practice SIO.

SIO by theoneofones July 30, 2022

sio 

literally the coolest and nicest and handsomest and tallest person alive.

person 1: who was that they were so cool
person 2: that was sio

sio by sawah< December 25, 2022

Sio'd 

to be extremely drunk to the point, sometimes, of being sick

oh my god, did you see her last night? she was sio'd!

Sio'd by Peers July 6, 2008

Sui Imago Odium (SIO) 

The mental condition where a person does not like to see his/herself in photographs or images irrespective of self-esteem or personal appearance.

"Sui" - Self in latin
"Imago" short for imago photographica - photograph in latin
"Odium" - To dislike in latin.

Case 1:
Person: Please don't post any photos of me! It really brings out my sui imago odium (SIO).

Case 2:
Person: No, I don't want any selfies! I really cant look at myself because of my Sui Imago Odium (SIO).

Sui Imago Odium (SIO) by PsychiatricEvaluator September 1, 2016