1. _ u _ _ i _ _ _ _ _ y (one word, 11 letters)
1. Fungibility
edit: I had to double check the correct spelling of the word to solve this.
i was a little faster than you with my post edit...
My guess for number five
5. Bitcoin-qt
5. Bitcoin-qt
here Tanaka-Wun was already faster...
5. Bitcoin-QT
Bitcoin Core (formerly Bitcoin-Qt)
Gained another knowledge about this word.
Bitcoin Core (formerly Bitcoin-Qt)
Gained another knowledge about this word.