鋭利|えいりeiri[1]atamadaka (head-high)

1. na-adjective, nounsharp; keen; acute
   鋭するどい舌したは絶たえず用もちいることによって、ますます鋭利えいりになる片刃かたはの道具どうぐである。↗

   A sharp tongue is the only edged tool that grows keener with constant use.

• Synonym鋭いするどいNeutral「鋭い」 is the everyday word for sharp blades and keen senses, minds, pain or criticism; 「鋭利」 is more written/formal and mostly describes blades.
• SynonymシャープNeutralLoanword for sharpness, clarity and keenness, often of lines, images and minds; also the ♯ sign. 「鋭利」 is mostly for blades.
• Synonym犀利さいりWrittenWritten/formal prose word for sharp blades and weapons or keen intellect; rarer than 「鋭利」 and close to it in meaning.
• Related鋭敏えいびんWrittenWritten/formal prose word for keen senses and a quick mind; not used for blades, 「鋭利」's main use.
• Antonym鈍いにぶいNeutral「遅い」 means slow or late; written 「鈍い」 it also means dull, so it is not a strict antonym of 「鋭利」. A dull blade is 「鈍い（にぶい）」.

In speech, 「鋭い」 covers sharp blades, senses, pain, remarks. 「鋭利」 is the written-style word for blade sharpness (「鋭利な刃物」). 「シャープ」 covers lines, images, minds; 「鋭敏」 is formal for senses and wits; 「犀利」 is a rare written near-match. A dull blade is 「鈍い（にぶい）」.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

1. 刃物はものなどがするどいこと。
2. 切れ味きれあじが良よいこと。
3. 賢かしこいこと。