1. See Hawhaw.

Nuttall's Standard dictionary of the English language By Nuttall, P.Austin

• hehe,
• ahv,
• hvea,
• ahl,
• ahn,
• ahx,
• raa,
• bahia,
• haya,
• bhaha,
• haga,
• chaha,
• cahga,
• dafa,
• daca,
• dahwa,
• odha,
• falha,
• haea,
• haia

• haw,
• hawaii,
• haw-haw,
• hay,
• Hai,
• Hae,
• hao,
• ha-ha,
• ha,
• Hah,
• Haye,
• Aha,
• Hau.

The adjective form of the word "haha" is "hilarious".