Infelicitous (adjective)

1. Unfortunate, unlucky, unhappy.
2. Not appropriate or suitable, inapt.

Origin:

From latin infelicitus, from in- ("not") + felix, felicis ("happy", "fortunat.e")

Examples:

1. Her wedding day was marred by infelicitous weather that ruined all of her plans.
2. The play received infelicitous reviews, causing the theater to close down soon after opening night.
3. He made an infelicitous choice of words that upset the entire audience.
4. The infelicitous timing of the announcement ruined the company's public image.
5. The decoration scheme for the party was an infelicitous blend of bright colors that made the room look chaotic.