The phrase "keen expression" is correct and usable in written English.
It is used to describe a facial expression that conveys interest or enthusiasm. For example: "He had a keen expression as he watched the magician perform his tricks."
As Kumudha, Jessica Rivera showed a secure, beautiful soprano voice, and Russell Thomas had moments of keen expression as the Prince.
The cairn terrier is a short-legged dog with a short, broad face fixed in a "keen" expression that is typical of the breed.
Later republican denarii gave keen expression to party politics, as when corn ears recorded circa 100 the purchase of grain by the quaestors Piso and Caepio, or the head of Ceres with ploughing oxen proclaimed the program of the Marians, or Sextus Nonius Sufenas advertised the games that he had staged as praetor.
"She has a keen expression and that dense, wiry coat.
The eyes are oval and dark, with an alert, keen expression.
It is perhaps Iraq's keenest expression of American-style capitalism: scores of investors and traders, some in pinstriped suits, others in ankle-length robes and head scarves, gather every Monday and Wednesday.
His hands are buried beneath the monumental pages of his official book, yet his keen, searching expression suggests that he is entirely equal to his task.
Its literature promises not lessons in technical mastery but in "keen awareness, personal expression, intensive listening and cross-cultural communication".
Some wonder what precedent this might set, especially for government authorities keen to stanch expression they think will inflame their populace.
These characteristics, joined with his very special keen, piercing, "varminty" expression, and his erect ears and tail are salient features of the breed.
Magda's passion for horses - she was a keen rider - found expression in The Enchanted Horse (2001), a magical tale about Irina, a child whose spirit feels crushed.
