look up any word, like the eiffel tower:
Don't mistake this for a double chin because there is a difference, it moves! A neck wave is when one moves and their head and during that time the flab hanging off their neck moves at a rapid pace almost scaring anybody who could be watching.
The 90 degree day wasn't so bad with grandmas' neck wave cooling me off!
by Jennec3ywyan June 07, 2011