The term 'NOT ALLOW TO ATROPHY' can be broken down into three words: 'NOT', 'ALLOW', and 'ATROPHY'. The three-letter solutions for each word are 'NO', 'LET', and 'WAS'. Therefore, the complete phrase can be summarized as 'Do not LET something ATROPHY'. ATROPHY is a medical term that refers to the wasting away of a body part or organ due to disuse or disease. Therefore, the phrase is suggesting that something should not be allowed to waste away due to lack of USE or illness.