The phenomenon whereby an awkward, unattractive, often pudgy-looking child grows up to be unbelievably hot.
The first observed case of The Neville Effect, and therefore the boy after whom the effect is named, Neville Longbottom (from the extraordinary Harry Potter series) is the typical example of this phenomenon. He looks a bit awkward and chubby when he is younger, but in a miraculous series of events, grows up to become a badass sex god. Other notable cases include Josh from Drake and Josh.
by lily247 June 12, 2012
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When a non-attractive person goes through puberty and becomes very attractive as a result.

First seen on Tumblr and Imgur, this term refers to Matthew Lewis's battle and victory over puberty.
"Have you seen Lisa since grade school?"
"No I have not, she really Neville Longbottomed. Damn."

"I was staying at my friend's house when her brother who I haven't seen in years walks in to say hello. I was in shock, as he Neville Longbottomed."
by Jamie McCrimmon August 22, 2013
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To become ridiculously more attractive than one's former self, primarily, but not exclusively, as a result of puberty. A pun on 'level up', referencing the unexpected transformation of Neville Longbottom (Matthew Lewis).
"Did you see what that kid from ET looks like now?"

"Yeah bro, I didn't expect him to Neville up like that."
by Lawren J. Reicher December 2, 2013
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To get significantly more attractive after going through the process of puberty.

Origin stems from Harry Potter, where the character Neville Longbottom (actor: Matthew Lewis) went from a dumpling shaped (but very sweet) 11 year-old to a daaaamn fine (and still very sweet) 25 year-old today.

The word was popularised by tumblr usage as both a noun and a verb.
Me looking in the mirror: I'd better Neville Longbottom by the time I get to uni, or I'm going to die alone. :/
Person returning home from uni: Is that...? Is that Susan?! Well she certainly Neville Longbottomed.
Person referring to their boyfriend: Nah, I'm not gonna break up with him. Yeah he's kinda pudgy, bit fingers crossed he'll do a Neville Longbottom!
by ICantThinkOfAUsername June 21, 2015
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BAMF.
Neville surprised us in the seventh Harry Potter by being such a badass. We now like to refer to him as BAMF. If he lets us.
Shall we review?

"Harry heard a scuffle and a shout, then another bang, a flash of light and a grunt of pain; he opened his eyes an infinitesimal ammount. Someone had broken free of the crowd and charged at Voldemort."
This badass would be Neville.

"The longer Harry looked at Neville, the worse he appeared: one of his eyes was swollen, yellow and purple, there were gouge marks on his face, and his general air of unkemptness suggested that he had been living rough. Nevertheless, his battered visage shone with happiness as he let go of Hermione and said again, 'I knew you'd come! Kept telling Seamus it was a matter of time!'
'Neville what happened to you?'
'What? this?' Neville dismissed his injuries with a shake of the head. 'This is nothing.'"

Finally the most BAMF moment of all:
"In one swift, fluid motion Neville broke free of the Body-Bind Curse upon him; the flaming Hat fell off him and he drew from its depths something silver, with a glittering, rubied handle-
The slash of the silver blade could not be heard over the roar of the oncoming crowd, or the sounds of the clashing giants, or of the stampeding centaurs, and yet it seemed to draw every eye. With a single stroke, Neville sliced off the great snake's head, which spun high into the air, gleaming in the light flooding from the Entrance Hall, and Voldemort's mouth was open in a scream of fury that nobody could hear, and the snakes body thudded to the ground at his feet-"
BAMF!
"If you're looking for Neville on the Marauder's map, he's labeled 'BAMF.'"

"Neville uses Nagini's blood as soy sauce."

"Neville Longbottom is what's beyond the veil."
by mathilde August 19, 2007
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The best person in Harry Potter. He full on stands up to Lord Voldemort in the last one. And your just like HELL YEAH!
Puberty also made him hot.
Person 1: DAAAAYUUUM, WHO'S DAT?
Person 2: Oh that brave hottie is Neville Longbottom
by strawberiiya July 30, 2011
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Pedigree: Almost pure Haze with just a hint of Indica (Northern Lights).

Strength: The most potent variety of its kind on or off the market. Not recommended for inexperienced smokers - too trippy - too profound.

Flowering Times: Indoors: should be started under 12 hours of lights. The earliest will finish in 14 weeks (25%). Those that take much longer than this are usually discarded as not practical.

Outdoors: should be grown in the Tropics + started just before the on set of autumn. Yields are surprisingly good - the longer flowering time is usually compensated with extra large yields, both in and outdoors. Not for the novice smoker or grower.

Neville's Haze has fluffy buds, a very long flowering period and delivers an intense rushing high. Neville's Haze marijuana has a complex aroma that almost smells like a plant other than a cannabis. Haze is a strain that could have many medical applications. Early flowering plant, can be grown both indoors and outdoors. Mostly Sativa. Good harvests can be expected. Neville’s Haze combines the original Haze - an almost psychedelic tropical Sativa - with one quarter Northern Lights - a powerful, heavy-hitting Indica. The result is a tall, thick-budding plant with a truly out-of-this-world high. This is not one for the casual smoker!

Neville’s Haze gains height like its Sativa parent, meaning that rooted clones and new seedlings can be put in a 12 hour flowering almost cycle immediately.
Stoner 1: Yo, i just copped some Neville's Haze.
Stoner 2: that shit is supoosed to be some super fiyah shit.
by 718phenom February 4, 2010
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