War cry declared right before collision with an object. Similar to "cowabunga," "oh shit" and that George of the Jungle yell which-I'll-be-damned-if-I-can-spell-out.

The term was made famous on the internet by a photoshopped Spider-Man comic strip in which our hero mistakes an overturned truck for his long-term arch-nemesis and proceeds to assault the truck by rope-swinging straight into the side of it.
Spidey: "My doctor's retarded. I don't have a brain tumor...say, if it isn't my old arch-nemesis, a truck!"

Narr: SPIDER-MAN GIVES CHASE!

(Spider-Man swings down toward the truck)

Spidey: "Fappo!"

(Spider-Man collides with truck)
by Siegfried Zaga May 21, 2005
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A word that most likely originates from the word "Fap" which is synonymous to "masturbate". To call someone a "Fappo" would then be similar to calling someone a "Wanker".
That guy is a total fappo!
by Calleh May 15, 2008
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