A term that describes the distortion that occurs when someone who’s an only child who grew up regularly distorting or misperceiving time intervals ballparks how long something is going to take.
When she gives me one of her only child timeframe estimates, I just double it so I don’t lose my mind.
by Dr Bunnygirl May 19, 2023

A terrible disease that typically effects only-children, but can occasionally strike people with siblings. It may also effect children whose parents divorce.
Symptoms include: playing mind games with members of the opposite sex, a cripling desire for instant gratification, the inability to compromise or share, and a total disregard for anyones thoughts or feelings but their own.
Symptoms include: playing mind games with members of the opposite sex, a cripling desire for instant gratification, the inability to compromise or share, and a total disregard for anyones thoughts or feelings but their own.
Example 1: Man, that girl is such a bitch- she wouldn't even spare a square! She has the worst case of only child syndrome I've ever seen!
Example 2: My boss has the worst case of only child syndrome ever! Every time I do something good he finds a way to slam me down just so he can feel better about himself.
Example 2: My boss has the worst case of only child syndrome ever! Every time I do something good he finds a way to slam me down just so he can feel better about himself.
by Andy Locoweed July 28, 2008

by TehRealBigDoge April 07, 2015

Most commonly affects teenage guys. Only Child Syndrome is a terrifying disease to those who approach the infected. It most commonly infects only children, but in some rare cases people with siblings have been known to have the disease. Symptoms are selfishness, inability to comprehend other people’s feelings, and overall brat-like behaviour. If rejected in any way, for example, a breakup, those who are affected by Only Child Syndrome will most likely isolate themselves in an attempt for attention. Do not, under any condition, pander to these pathetic cries for attention. It’s all for a bit of drama.
Person 1: Mate, Alex told me that I would let him have my phone if I truly loved him!! How lame is that?
Person 2: Ignore him, it’s Only Child Syndrome.
Person 2: Ignore him, it’s Only Child Syndrome.
by The better Anonymous January 17, 2018

A person who has similar symptoms to that of an Only Child but is not necessarily an only child. Generally they are quiet, sensible and mature for their age, serious, kind, shy and slightly awkward, and don't get bored easily. This condition typically onsets in adolescence. It is difficult to imagine an only-child type living and interacting with a sibling, even if they do actually have a sibling.
1. "No way, dude, Emily has a sister? She's such an only-child type though!"
2. "Yeah, I knew you didn't have any siblings, you're an only-child type."
2. "Yeah, I knew you didn't have any siblings, you're an only-child type."
by whatwhatwhat77 August 07, 2012

When an only child suddenly gets siblings (step siblings/baby brother or sister) and realizes that the adult attention he or she once enjoyed so much and took for granted suddenly is scarce, resulting in a feeling of sadness and loss.
Peter was used to being the only child, but due to his mother's remarrying, he got new step siblings. Not being used to fight for attention from his mother, he has hit with an only-child-hangover.
by tabu.post May 11, 2011

The self-centered attitude and actions that a large percentage of people with no siblings make their calling card.
Lars: "Why does he think everyone needs to worship the ground he walks on?"
Marv: "Dude it's just only child syndrome."
Marv: "Dude it's just only child syndrome."
by Albiesaurus Rex December 09, 2008
