acute has 13 distinct synonyms spread across 4 of its 7 senses. Each sense below keeps its own list, because a synonym belongs to a meaning and not to a word: swapping one sense's substitute into another sense's sentence is how a thesaurus makes writing worse. Its 2 recorded opposites are chronic, obtuse.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
having or experiencing a rapid onset and short but severe course
“acute appendicitis”
having or demonstrating ability to recognize or draw fine distinctions
“an acute observer of politics and politicians”
of an angle; less than 90 degrees
ending in a sharp point
1 of the 7 recorded senses carries no synonym, antonym or related term, so it is not shown above. Every sense, with its definition and examples, is on the full entry for acute.
Synonyms, antonyms and the broader and narrower relations for acute come from Princeton University’s WordNet. Full sources and licences.