acute:  Acute derives from Latin acūtus ‘sharp’ (which was also the source of English ague). This was the past participle of the verb acuere ‘sharpen’, which in turn was probably formed from the noun acus ‘needle’. Like the related acid, acetic, and acrid, it can be traced back to an Indo-European base *ak- ‘be pointed’, which was also the ultimate source of oxygen and edge. => acetic, acid, acrid, ague, cute, edge, oxygen
late 14c., originally of fevers and diseases, "coming and going quickly" (opposed to a chronic), from Latin acutus "sharp, pointed," figuratively "shrill, penetrating; intelligent, cunning," past participle of acuere "sharpen" (see acuity). Meaning "sharp, irritating" is from early 15c. Meaning "intense" is from 1727. Related: Acutely; acuteness.