The term 'not sharp or flat' can be summarized by two crossword solutions: 'tuned' and 'onkey'. 'Tuned' is an adjective that describes something that has been adjusted to the correct pitch or tone. It is often used in reference to musical instruments, such as a guitar or piano, which must be tuned before they can be played. 'Onkey' is an adverb that means 'in tune' or 'in harmony'. It is often used to describe a performance or piece of music that is performed accurately and without any mistakes. Both words refer to the idea of something being in tune or in harmony, which is the opposite of being sharp or flat.