The term 'not approximate' can be broken down into four crossword solutions: EXACT (5 letters), SPECIFY (7 letters), DESIGNATE (9 letters), and DISSIMILAR (10 letters). EXACT means to be precise and accurate, without any errors or mistakes. SPECIFY means to give a detailed description of something, often in writing. DESIGNATE means to assign a particular name, title, or role to someone or something. DISSIMILAR means to be different from one another, not similar in any way. All four of these words are related to the term 'not approximate, ' as they all refer to being EXACT, precise, and different from one another.