"Narrowed eyes" refers to when someone squints or tightens their eyelids, usually as a sign of suspicion, skepticism, or intense concentration. Full definition
That's something I'm narrowing my eyes at, the word «infinite». (fraghero.com)
Larry «Major Nelson» Hyrb was last seen narrowing his eyes suspiciously as he stared out of a top floor window to across the road, where Sony CEO Kazuo Hirai sat on a park bench, waving enthusiastically and in an «overly friendly» manner. (pointandclickbait.com)
Yet the palazzo's current owner, a stiffly coiffed blonde with narrow eyes, was unimpressed by the presence of Gioni and other star curators (Francesco Bonami, Caroline Bourgeois, Nicholas Cullinan) seated in her elegant salon with artists Miroslaw Balka, Sarah Sze, and Laurie Simmons; dealers Larry Gagosian, Philomene Magers, Lorcan O'Neill, and Philippe Ségalot; and collectors Patrizia Sandretto Re Rebaudengo, Maja Hoffmann, Marie Josée Kravis, Marella Agnelli, and Neda Young. (artforum.com)