Gruntle: 1. To utter a little or low grunt. Said of swine, occas. of other animals; rarely of persons.2. To grumble, murmur, complain.fromed from the verb `grunt"Gruntled" as the opposite of disgruntled is merely a comical counterpoint, as disgruntled is a frequentative of grunt. (I should add: the 'dis' seems to be an intensifier here, not a reversal, as in disannul as opposed to disengage) First OED citation is from Wodehouse, if that is any indication.