onee-sama 

A Japanese term made of these parts:
1. The 'o-' prefix, indicating a respectful tone.
2. 'nee', meaning 'sister'.
3. The '-sama' suffix, an honorific denoting extreme respect as might be used when addressing noble figures or gods.

Onee-sama is an unusual, overly formal way of referring to one's sister. For most everyday purposes, the neutrally formal 'onee-san' or familiar 'onee-chan' would suffice: only those raised in highly formal settings would even contemplate using 'onee-sama' in a non-sarcastic way (as one might say in English 'oh of course your highness').

'Onee-sama' is a term mostly popularised by manga and anime, specifically shoujo-ai (love between young girls) series set in high-class boarding schools (see Strawberry Panic for a textbook example). Because of this association, 'onee-sama' is inextricably tied to the more elegant side of the shoujo-ai genre: a young girl using the term to address an older, unrelated girl could be hinting at a deeper relationship between the two of them. Or they could just be messing with you.

IRL (sort of): "Onee-sama, I hope you aren't labouring under the misapprehension that your seniority over me justifies you putting on airs."
Shoujo-ai fantasy: "Onee-sama, would you please become my soeur?"

onee-sama by Kazzius November 22, 2013

onee-chan 

Onee-chan is Japanese for older sister.

"Good morning, Onee-chan"

onee-chan by Makayo July 12, 2006

number onee 

"number onee" is a phrase rather than word. It is the international sign of approval amongst dirtbags, scumbags, and disgusting people. When you call someone "number onee" this should be accompanied by a raised arm, closed fist, with your index finger pointed at the person and wagged at them. Now, the phrase does not always need to be accompanied by the gesture and the gesture does not need the phrase to get the point across; they are best used together but are just as sufficiently understood seperatly.

(Ale hits on 13 year old girl; he is 26)
Matt: You're number onee
Ale: Omg thanks man!

(Matt is getting a bj in the woods, Sammy passed by, they make eye contact, Sammy gives Matt the "number onee" gesture, Matt cries one tear of happiness)

number onee by capn caboto September 16, 2014

Oneesan 

Japanese word for "big sister"

"oneesan! Mom said to clean your room!"

Oneesan by KittyKinetc April 9, 2008

oneesa

Oneesa is the name that one cool kids get people named oneesa get lots of friends and boys 😉

Boy1: oh she’s cute what’s her name?
Boy2: Oneesa!
Boy1: oh say less!

oneesa by Shy with a C October 24, 2020

OneEliteMofo 

One who was underestimate but destroyed any and all who dared to call him out.

Your not bad, but no where close to OneEliteMofo

You lost badly, but thats what happens when you go against a OneEliteMofo

Its only natural to leave the scene with your tail between your legs when you go vs a OneEliteMofo

OneEliteMofo by Darren Macomb October 29, 2007

Oneer 

An absolute madlad. He is very cool but sometimes is too obsessed with pick-up lines.

That guy is an Oneer.

So cool! Just make sure he doesnt use a pick-up line on you.

Oneer by GajarKaHalwa September 8, 2020