All fields of technology and design needs terms to define complex meaning regarding their subject. This is my attempt to create a few such terms for user experience design. Please help out through the comments or DM me on twitter!
Resistance refers to the resistance of experiencing the design. This can encompass the macro experience of, for example, music:

• Find a song you like (resistance)
• Purchase the song (resistance)
• Listen to the song

But resistance can also mean the micro experience of the music:

• BPM might not match the listeners mood (resistance)
• Singers voice might hit strange notes (ever listened to death metal or opera and hated it despite a catchy tune? resistance)

So resistance can build both from the users cognitive or psychological experience of the product as well as the practical obstacles the user has in order to experience the intended design.

Since all negative values are experienced as twice as important compared to a positive value, resistance is important to reduce.

Reducing resistance as much as possible is in fact the process of making something accessible but the term is a lot more exact. Defining what we’re really intending to do.

Reduce resistance of user experience, make the user experience flow in using your experience!