There's no "standard" way to do that, but (although I haven't tried) it shoudl be possible.
There is a
DataGridView.CellToolTipTextNeeded Event[
^] which allows you to set the ToolTip text "on the fly". The complication will be working out which word you are over!
That's probably going to need a bunch of calls to MeasureString and a degree of trial and error to get right.
But yes, with some effort it should be possible.