Basing a definition on context, I would define judgmental as ‘judging based off assumption’. This form of presumptuous judgment, I believe, can be divided into three forms; judgmentalism as relating to the soul, actions, and arguments. To be me, I’ll define them as ‘essential judgmentalism’ ‘actional judgmentalism’ and ‘positional judgmentalism’.
For myself especially, I would say that essential judgmentalism is the easiest to fall into, especially in debates. In general, it’s when you assume things about a person’s state of soul, intelligence, or any other facultive part of his being based on insufficient assumption. I do this in debates a lot, judging people mainly by the way they write and argue; granted I rarely if ever let it show, but… I probably (or most definitely) owe a general apology to most people I debate with for presumptions on my part of this nature. Now obviously it is not only in discussion that a person falls into this; dress, mannerisms, and other suchlike accidentals of a person's life also are used in it.
Now, essential judgmentalism does not include those judgments which a person makes regarding the state of a person’s soul or facultive abilities through due knowledge; for instance, ones’ spiritual director or confessor of many years would have the ability to make non judgmental judgments of you, while a random priest you go to confession behind the screen would not, unless you gave him quite a bit of details. A religious example, I know, but the best I could think up on the spur of the moment.
Actional judgmentalism does not judge the person directly, but rather assumes the nature, or other properties of an action without due knowledge. So for instance if I see someone walking out of a store with a bag, and automatically assume they’re a shoplifter (yes, paranoid me does this sometimes, although not quite with this example) then I am engaging in this form of judgmentalism. The second part is when we see an entire action, and based on that knowledge judge a person’s guilt in said action without due knowledge of that person’s intent and knowledge; in short disregarding the three points of guilt; evil action, knowledge, and will.
Positional judgmentalism rests upon the interpretation of positions or arguments of a person without due knowledge of them. I do this a lot, usually because I misread someone’s argument and argue against, well, what they don’t hold. But it also applies to when one takes either a vague or very short point or position and drawing from possible inference either refute a position that the person does not hold, or twist the position to something that the person did not intend. While this can stem from accidental assumption, it is nonetheless an assumptive judgment, and thusly judgmental.
None of these, of course should be confused with judgment, which is of itself by no means wrong (making judgments being what we do by nature of being rational.) Rather, judgmentalism is that judgment which relies heavily on assumptive reasoning, whether judging a person, their action or their positions.