As I understand it, it does actually mean "free of locks", since a lock-free algorithm, by definition, cannot be implemented in terms of classical locks (typically mutexes) [1] [2]. It's "free of lockups" by virtue of, well, being free of locks.
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