1. Cheerfully irresponsible
   - carefree, devil-may-care, freewheeling, happy-go-lucky, harum-scarum 
2. Dazed from or as if from repeated blows
   "slaphappy with exhaustion"
   - punch-drunk, silly

See also: confused, irresponsible

• commandant
• commandeer
• commander
• commander in chief
• commandership
• commandery
• commanding
• commanding officer
• commandment
• commando
• comme il faut
• commedia dell'arte
• commelina
• Commelinaceae
• Commelinales
• Commelinidae
• commemorate
• commemorating
• commemoration
• commemorative
• commemorator
• commence
• commencement
• commencement ceremony
• commencement day