1. cheerfully irresponsible or carefree
Usage: informal
2. dazed or punch-drunk, especially from repeated blows
Usage: informal

Examples

• The teenagers were slaphappy after staying up all night at the party.
• He had a slaphappy attitude about spending money he didn’t have.
• The boxer looked slaphappy after taking so many hits to the head.
• She felt slaphappy from lack of sleep and too much caffeine.
• Their slaphappy approach to the project worried the supervisor.
• The comedian’s slaphappy humor kept the audience laughing.