1. Fungibility
edit: I had to double check the correct spelling of the word to solve this.
Cygan is faster than you, you're late by a minute. edit: I had to double check the correct spelling of the word to solve this.
My guess for number five
5. Bitcoin-qt
Dude that's my guess 5. Bitcoin-qt
5. isn't-right
Fill in the blanks only this is not a scrabble. Oh sorry for that, i never knew you have already made the post while i was busy in search for the words, @pmalek please take not should the answer be correct, Tanaka-Wun is the winner.