There are a multitude of synonyms for the word "trimmingly", all of which convey a sense of neatness, tidiness, and attention to detail. Some alternatives might include "neatly", "precisely", "orderly", "meticulously", "prudently", "carefully", "tidily", "methodically", or "systematically". Depending on the context, other words that might work well as synonyms include "efficiently", "economically", "minimally", "austere", or "sparsely". Ultimately, the best synonym for "trimmingly" will depend on the specific usage and tone of the sentence or phrase, as well as the writer's intended meaning and emphasis.