The word 'Boosties' is the name given to a pair of shoes, in particular, the adidas ultra boost. However, this can be applied to whatever shoe you feel deserves the name 'Boostie'. It can also be used to describe how you are feeling. The opposite of feeling 'dusty' is to feel 'Boostie' which is like the feeling of opening a new pair of shoes.
Owen: " I really like these boosties I bought yesterday, I think they're really good at being boosties. "
Joe: " I need to get myself a pair because I've been feeling dusty lately"
Short-hand for the word floccinaucinihilipilification, meaning the estimation of something as valueless (encountered mainly as an example of one of the longest words in the English language).