Tightening is a term used to describe the process of making something tighter or more confined. FLEXING (7 letters) is the act of bending or stretching something, while TENSING (7 letters) is the act of making something taut or rigid. CONSTRICTION (12 letters) is the act of making something narrower or smaller, and SHORTENING (10 letters) is the act of reducing the length of something. CONSTRICTING (12 letters) is similar to CONSTRICTION, but it involves making something narrower or smaller in a continuous manner. Finally, CONTRACTION (11 letters) is the act of making something shorter or smaller.