Nigglingly is an adverb that means to do something in a petty or trivial manner. The word can be replaced by synonyms such as fussily, faulting or nitpicking. Other synonyms for the word nigglingly include carpingly, picayunely, quibblingly and cavilingly - which all suggest an excessive attention to detail and a tendency to criticize. These synonyms are useful when describing someone who is very particular or hyper-critical about small or unimportant details. Choosing the right synonym for any given situation can help to add nuance and depth to your writing, and it is always a good idea to expand your vocabulary when writing professionally.