Question

What is the opposite of,at lenght,rigid and tranquility

Answer 1

rigid is something that isn't flexible at all. The opposite of it flexible, like rubber. 

Answer 2

The opposite of length would be width, because length is measuring distance, and width is measuring height and thickness. The opposite of rigid would be flexible, broken, or soft, because rigid means 'stiff, strict, or severe'. The opposite of tranquility would be calamity or commotion, because tranquility is something calm or inactive.