from Latin 'acutus' meaning sharp or pointed
The word acute is an adjective. Acute describes something that is urgent.
He's acute little freak in the bed!
There are two acute in the letter k
The word acute refers to angles, not sides. It does have all three angles are acute (less than 90°)
An angle that is less than 90º is acute.
The acute angle looked like a sharp spike.
This is an acute infection. It does not come gradually.
The patient experienced an acute pain in their chest, prompting the medical team to take immediate action.
An angle that is less than 90 degrees is said to be acute.
I think the word your looking for is equilateral triangle
Serious, critical.
obtuse?