Noun.
An impressive, nerdy, and often
useless mental or physical ability.
Adjective.
A term used to describe something that is nerdy and
cool at the same time.
It is the accidental brainchild of Baroness
Susan Greenfieldidiot, who, on one of her regular rants warning about the dangers of the internet on the brain, said that modern technology would result in a generation of people obsessed with 'yuck and wow'; this was mis-transcribed, and subsequently printed as 'yaka-wow'.
Its dual use as a noun or an adjective is similar to that of the
irish word craic. It is also extremely phonologically pleasing as a phrase.