When a person who used to be somewhat awkward and not attractive, though not necessarily unattractive, becomes extremely beautiful. Because this person used to be unattractive, bitter and jealous people assume they are emotionally damaged and scarred. Hence, they believe the aforementioned beauty is mentally demented, while they themselves are sympathetically retarded.

Ugly Duckling Syndrome is an excuse to undermine the physical and inner attractiveness of a blossomed beauty.
"Wow! That girl used to be really awkward! What happened! I'm sure she MUST have done some kind of plastic surgery to get that face. I guess she's really insecure then, and she probably has ugly duckling syndrome."

"No you dipshit, she just went through puberty."
by Mr. Lipshitz June 15, 2009
Get the ugly duckling syndrome mug.
A Girl who grew up all her life unattractive until High School or College when she then "Blossomed" into a really hot girl. Unlike naturally pretty girls though, her self-esteem is pretty low (As it'll almost permanently be for life) but, she has a good heart, personality, and soul because that's all she could afford to have when she was unattractive. Also, any girl with UDS, will go out with any guy cause to her "Looks Doesn't Matter. As long as they have a good Sense of Humor." As long as they never realize that they're a Ten, they'll always be humbled and down to earth.
A girl with the Ugly Duckling Syndrome or UDS, is The Perfect Catch! She's a Perfect 10 both in and out and she'll do whatever you want her to do! She'll date anybody and could never do anything wrong to you because to her, she's lucky just to have you!
by G-Union 2 August 2, 2004
Get the Ugly Duckling Syndrome mug.
A person who did not develop fully (therefore making them ugly) up until highschool or later and becomes pretty and they are really nice and have low self-esteem.
Stephanie was a ugly fuck but she was nice, but now she is hot and doesnt even know it (!bong!)
by Tical February 5, 2004
Get the ugly duckling syndrome mug.
Addition to the entries above:

A sudden awakening from UDS can have extreme big head reactions. This unfortunate turn of events is one of the primary foundations of the camwhore , a girl who has been sheltered/shunned from sex - but suddenly realizes she "has it".
UDS + TLC + netmeeting.exe = camwhore
by SaussyBurbank April 7, 2004
Get the ugly duckling syndrome mug.
When a person with a good personality is actually attractive.
When you set me up on that blind date, you should have told me she had the Ugly Duckling Syndrome, you scared me when you told me she had a good personality.
by Hyland February 2, 2004
Get the ugly duckling syndrome mug.
The act of inhaling hookah/cigarette/cigar smoke and then blowing it into a girl's pussy. The girl then queef's the smoke back out into the air.
Ashley got a Utah Ugly Duckling from Jeff at the party.
by Thanatos Nex March 7, 2010
Get the Utah Ugly Duckling mug.