I was so disgusted by his behavior. First his demeanor at the moment of silence for Justice Scalia at the beginning of the debate.
While all the other candidates bowed their head, he stood there like a klutz with his head held high, as if the death of Justice Scalia meant nothing to him. (As a democrat that he still is despite claiming he is now a Republican, it probably meant nothing to him.
When I first ready about Trump being "petulant", I had a pretty good idea what it meant, but I looked it up to make sure.
There is no better term to describe Trump than PETULANT
* childishly sulky or bad-tempered.
* peevish, bad-tempered, querulous, pettish, fretful, cross, irritable, sulky, snappish, crotchety, touchy, tetchy, testy, fractious, grumpy, disgruntled, crabby