I Love Words

THE RIGHT WORD
A knife can be sharp, even keen, but it can’t be astute. While keen and sharp mean having a fine point or edge, they also pertain to mental agility and perceptiveness.

You might describe someone as having a keen mind, which suggests the ability to grapple with complex problems, or to observe details and see them as part of a larger pattern (: a keen appreciation of what victory would mean for the Democratic Party), or a keen wit, which suggests an incisive or stimulating sense of humor.

Someone who is sharp has an alert and rational mind, but is not necessarily well grounded in a particular field and may in some cases be cunning or devious (: sharp enough to see how the situation might be turned to her advantage).

An astute mind, in contrast, is one that has a thorough and profound understanding of a given subject or field (: an astute understanding of the legal principles involved).

Like sharp, shrewd implies both practicality and cleverness, but with an undercurrent of self-interest (: a shrewd salesperson).

Acute is close in meaning to keen, but with more emphasis on sensitivity and the ability to make subtle distinctions (: an acute sense of smell).

While a keen mind might see only superficial details, a penetrating mind would focus on underlying causes (: a penetrating analysis of the plan’s feasibility).

Perspicacious is the most formal of these terms, meaning both perceptive and discerning (: a perspicacious remark; perspicacious judgment).

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Via Oxford American Dictionary definition of the word “keen”

Source: oup.com