fun vs have a laugh

fun

• To tease, kid, poke fun at, make fun of. 

• playful, often noisy, activity. 

• amusement, enjoyment or pleasure 

• Enjoyable or amusing. 

• Whimsical or flamboyant. 

have a laugh

• To joke; kid around. 

• To enjoy oneself; have fun. 

• To laugh.