Sidelong
/ˈsaɪdlɔːŋ/
Definition 1 of 2
Pro Tip 1/3Subtle Observation
Used for describing a way of looking at something or someone without being obvious. 
In the meeting, she cast a sidelong glance at the clock, eager for a break.
Pro Tip 2/3Hidden Implications
Can imply secrecy, disapproval, or interest without direct confrontation. 
His sidelong smiles suggested that he knew more than he let on.
Pro Tip 3/3Physical Position
Describes someone's stance or posture turned to one side. 
The actor posed sidelong for the photograph, looking suave.