Use 'incongruous' to describe something strangely out of place in its surroundings or context. A palm tree in Alaska would be an incongruous sight.
Pro Tip 2/3
Clashing Elements
Describe elements that clash or do not blend well together as 'incongruous'. The traditional painting looked incongruous on the modern building's wall.
Pro Tip 3/3
Nuanced Tone
'Incongruous' often implies a subtle, sometimes humorous contrast, not just direct opposition. Her punk rock outfit was incongruous at the classical music concert.