Use 'wonky' for tangible items like furniture or machinery when they're uneven or broken. Avoid placing your laptop on that wonky desk; it could fall off.
Pro Tip 2/3
Not about People
'Wonky' should not be used to describe people who aren't standing straight. The old fence looks wonky, not the man leaning against it.
Pro Tip 3/3
Situational Use
Apply 'wonky' to temporary situations where things don't work as expected. Sorry for the delay, our printer is a bit wonky today.