To be in a very happy/random state, often being extremely spontaneous, and laughing at almost anything. Usually arises from extreme tiredness or light-headedness.
John was laughing for an hour today because someone said 'turtle!' He's being really wiffly.
by Andor Gillian June 21, 2011
1 more definition
Rhymes with "sniffly".
I'm all congested and my nose is sniffly-wiffly.
by Heartichokes May 10, 2008