steal a glance (at someone or something)
To look at someone or something very quickly and discreetly. That boy just stole a glance at you again! I think he likes you! I stole a glance to see if the teacher was watching us.
steal a glance at someone or something
Fig. to sneak a peek at someone or something. He stole a glance at his brother, who appeared to be as frightened as he was. Karen stole a glance at her watch and yawned.
steal a ˈglance/ˈlook (at somebody/something)
(written) look quickly at somebody/something, so that nobody notices you looking: He stole a glance at her out of the corner of his eye.