Someone who is daft, idiotic, or criminally insane.
That guy's a total giggler; he was all but drooling.
by Old Bollinger April 18, 2009
No one is quite sure what he's laughing at, but as soon as the office has finally become quiet you can count on hearing his high-pitched tee hee hee
Some think the giggler has discovered the Warn button on Instant Messenger and this is the source of his joy.