The term 'not stiff' can be described by a variety of words, all of which have been used as solutions to a crossword puzzle. The first word is 'AGILE, ' which means having the ability to move quickly and easily. The second word is 'SPRY, ' which means active and energetic. The third word is 'TIP, ' which means to move lightly and quickly. The fourth word is 'LIMP, ' which means lacking strength or stiffness. The fifth word is 'LITHE, ' which means having a graceful and FLEXIBLE body. The sixth word is 'FLEXIBLE, ' which means able to bend without breaking. The seventh word is 'LIMBER, ' which means having the ability to move and bend easily. All of these words describe the term 'not stiff' in different ways, emphasizing the idea of being able to move freely and without stiffness.