Acute (adjective)

1. Having a sharp point or tip.
2. Having a sudden and severe onset.
3. Having a high degree of intensity.
4. Having a keenness of perception or insight.

Origin:

From latin acutus "sharp, pointed".

Examples:

1. The acute angle was measured.
2. He has an acute case of the flu.
3. The acute pain in his chest was caused by a heart attack.
4. She has an acute sense of smell.
5. His acute business sense made him successful.