management at my company always say this, always followed by "but nevertheless we are doing well" (or something similar)"Challenging"
I see this a lot when companies see profits/turnover dip, and the chairperson goes on record to say something like "It's been a challenging year"
In other words you've had a tit year, you've made some bad decisions, your shareholders are on your back, and you're about to get the boot.
Just say it like it is - you're fooling nobody!