From [0]: "An algorithm is lock-free if, when the program threads are run for a sufficiently long time, at least one of the threads makes progress (for some sensible definition of progress)."
Note that there's also the distinction between lock-free algorithms and lock-free data structures. Crossbeam is the latter, I believe (but I could be wrong).
[1] https://www.cs.cmu.edu/~410-s05/lectures/L31_LockFree.pdf
This environment only happens to exist in very specific and uncommon settings, so it's not a generally useful concept for lock-free programming. It's common in the linux kernel to see spinlocks taken in sections which have disabled all interrupts, for example, but this is not an environment that normal programs can live in.
I think the key paragraph from the Wikipedia article is:
"In particular, if one thread is suspended, then a lock-free algorithm guarantees that the remaining threads can still make progress. Hence, if two threads can contend for the same mutex lock or spinlock, then the algorithm is not lock-free. (If we suspend one thread that holds the lock, then the second thread will block.)"