Other forms: acutest; acuter; acutes
Use the adjective acute for when you want to describe something as sharp or extremely serious.
The word acute is one word; it's not two words, nor does it have anything to do with something small, cuddly, and pretty! Acute really means "sharp" or "severe" or "intense" and modifies certain kinds of angles in geometry or describes a certain kind of illness of short duration. The English word apparently entered the language during the sixteenth century from the Latin root acutus, which means "sharp" or "pointed."