1. Not working according to design (of programs). This is the mainstream sense. 2. Improperly designed, This sense carries a more or less disparaging implication that the designer should have known better, while sense 1 doesn't necessarily assign blame. Which of senses 1 or 2 is intended is conveyed by context and nonverbal cues. 3. Behaving strangely; especially (when used of people) exhibiting extreme depression.
[glossary]
[Reference(s) to this entry by made by: {break}{gronked}{wonky}]