acuteness

From acute +‎ -ness.

acuteness (usually uncountable, plural acutenesses)

1. The quality of being acute or pointed

   the acuteness of an angle

2. (of the senses or feelings) The faculty of precise discernment or perception; sensitiveness

   By acuteness of feeling, we perceive small objects or slight impressions.

   By acuteness of intellect, we discern nice distinctions.

3. Shrillness; high pitch; – said of sounds.
4. (medicine) Violence of a disease, which brings it speedily to a crisis.
   • 1886, Robert Louis Stevensony, Strange Case of Dr Jekyll and Mr Hyde:

     At the time, I set it down to some idiosyncratic, personal distaste, and merely wondered at the acuteness of the symptoms; but I have since had reason to believe the cause to lie much deeper in the nature of man, and to turn on some nobler hinge than the principle of hatred.

5. Shrewdness, quickness of mind

• acuity, sharpness, acumen, keenness

• acutance