Niggle and Question mark

Niggle verb - To make often peevish criticisms or objections about matters that are minor, unimportant, or irrelevant.

Question mark and niggle are semantically related. In some cases you can use "Question mark" instead a noun "Niggle".

Question mark noun - A punctuation mark (?) placed at the end of a sentence to indicate a question.

Niggle and question mark are semantically related. Sometimes you can use "Niggle" instead a noun phrase "Question mark".