Sharpness, acuteness, and insight, however keen, and penetration, however deep, fall short of the meaning of acumen, which implies also ability to use these qualities to advantage. There are persons of keen insight and great penetration to whom these powers are practically useless.

J. C. Fernald, English Synonyms and Antonyms (1914)

Example sentences

depth Compared with his father, he is lacking in depth.
piercing He hid his belly button piercing from his parents.
incursion We should resist the incursion of the English language.

Popularity over time

Word	1850 → 2019	Trend
penetration		falling
depth		falling
piercing		rising
incursion		rising
perforation		steady

Use in printed books, per decade from 1850 to 2019.

By length

3 letters: wit¹
5 letters: depth¹
6 letters: acumen³
7 letters: insight²
8 letters: entrance², judgment², piercing², subtlety³, prudence², keenness, sagacity
9 letters: judgement², sharpness², incursion³, acuteness³
10 letters: shrewdness², astuteness³
11 letters: discernment³, perforation⁴
12 letters: intelligence⁴, perspicacity
14 letters: discrimination⁵

The small number after each word is its number of syllables (acumen³ = 3 syllables).

In other languages

Français: pénétration
Italiano: penetrazione
Deutsch: Penetration