Incongruous (adjective)

1. Not in harmony or agreement; not congruent.
2. Not suitable or appropriate in the circumstances; not fitting.
3. Not consistent or coherent with the surrounding elements.

Origin:

From the latin word "incongruus" meaning "not fitting" or "not congruent".

Examples:

1. The clown's serious expression was incongruous with his silly costume.
2. His formal attire was incongruous at the beach party.
3. The serious tone of the conversation was incongruous with the lighthearted subject matter.
4. The incongruous combination of flavors in the dish made it unappetizing.
5. The incongruous behavior of the students was disruptive to the class.