inscrutable
He put his pen away, watching her inscrutably.
She gave him an inscrutably intense smile.
Dave looked at him inscrutably.

SMART Vocabulary: related words and phrases

Not showing or feeling emotions
anodyne
anti-sentimental
belie
bite
bite your lipidiom
frozenly
glaze
hard-bitten
hardened
icily
poker face
reserved
reservedly
sphinx-like
stiff upper lip
unmoved
unprocessed
unresponsive
unresponsively
unresponsiveness

Examples of inscrutably

inscrutably
I have always been bewildered by the old meme about her inscrutably blank expressions.
From The New Yorker
As these things often do, the missive prompted a piling on of similar tales of inscrutably weird or profoundly rude dating messages.
From The Atlantic
He loomed at the back of her thoughts, inscrutably dark and romantic.
From Project Gutenberg
She smiled inscrutably and turned to look at the coop, clapping her hands in delight.
From Project Gutenberg
And the sick girl smiled wanly, inscrutably, the smile of one who knows what he will not say.
From Project Gutenberg
His keen old face inspected her inscrutably for a while.
From Project Gutenberg
With quiet attention, the girl regarded him, then smiled inscrutably.
From Project Gutenberg
But he didn't tell her; he smiled inscrutably.
From Project Gutenberg
He met that searching gaze as inscrutably as he had learned to endure the scrutiny of his opponent at the poker table.
From Project Gutenberg
The tall captain considered him inscrutably, he, the final arbiter of fates.
From Project Gutenberg
Warrant in one large hand and gavel in the other, he inscrutably stared upon the expectant voters for a weighty minute.
From Project Gutenberg
The old chief listened, inscrutably, his unwavering gaze fixed upon the earnest speaker.
From Project Gutenberg
She must know that he couldn't explain his invasion of her house through that inscrutably closed door.
From Project Gutenberg
There is something inscrutably delightful about a girl's way of thinking one thing and doing another.
From Project Gutenberg
These examples are from corpora and from sources on the web. Any opinions in the examples do not represent the opinion of the Cambridge Dictionary editors or of Cambridge University Press or its licensors.