gignant
Gignant is an adjective that describes a state of excessive, unfocused giggling. When one is in the throes of gignance, they have trouble holding it together and have no idea at what they are laughing.

The proper spelling would be "gignorant," but it has been shortened for phoenetical purposes.
"Tyrone hit that blunt three times and turned into a gignant fool, we didn't know what the fuck he was laughing at."