She looked at him with a blank expression, not giving anything away.
blank look
Frequency:
60
%
He gave her a blank look, unsure of what she was talking about.
blank gaze
Frequency:
50
%
She met his blank gaze with a sense of unease.
blank eyes
Frequency:
45
%
His blank eyes revealed nothing about his thoughts.
Idiomatic Expressions for blank stare
Phrase: met with blank stares
Meaning: to be met with a lack of understanding or response
Usage: When the teacher asked the class a difficult question, she was met with blank stares.