A word denoting a typical liberal, likely to support the Democratic party without question and soften the edge of any leftist movement that threatens the establishment. Derives from the desire for the American parties (Democrats in particular) to be 'Big Tent'.
Tentheads often try to disarm any sort of
radical movement in the name of 'keeping
peace' and then go on to cry about needing the kind of change those
radical movements would have brought.
Also synonymous with 'Shitlib' and 'Libtard' (though Tenthead is more often used in leftist circles.)