Complacent (adjective)

1. Self-satisfied, especially when unaware of or indifferent to danger or trouble.
2. Smugly contented.

Origin:

The word complacent is derived from the latin word "complacens" meaning "pleasing" and "complacere" meaning "to please." it was first used in the early 17th century.

Examples:

1. He was complacent about his business, not realizing how much competition he had.
2. She was complacent about her job performance and didn't see the need for improvement.
3. He was too complacent to see the warning signs of the impending financial crisis.
4. The company's complacent attitude towards innovation ultimately led to its downfall.
5. The complacent patient ignored the warning signs of the disease and did not seek treatment.