Is there another way of saying something is 'user-unfriendly'?
I would go with 'unfriendly'. The 'user' part is redundant, particularly in the case of software. In fact uses of it outside the scope of software are really "loans" of the term.
In any case I would argue that most synonyms of "unfriendly" don't convey the same precision, and have fundamentally different meanings. Software can be "unfriendly" because it's cumbersome (it takes too many gestures to acomplish a task) even if it's easy to use (it's always obvious what the right gesture is). Similarly words like "complex", "slow", "ugly", "poorly designed", "unintuitive" etc all cary degrees of precision that are either more or less precise than "unfriendly".
So, I think "unfriendly" really is the best choice when you want to convey a "general defect in the usability or character of an interface". The alternatives almost always convey something fundamentally different.
- Lotus Notes, anyone so afflicted will understand immediatly
- User Hostile, bit extreme but some systems really are
- Bureaucratic, probably the most useful expression in describing an unhelpful and tedious to use interface.
The best real life description of a poor user interface I ever heard was "As user friendly as a cornered rat".