The word "sidelong" is correct and usable in written English
You can use it to describe a type of glance or look, often a quick, furtive one, that is directed sideways. Example: The thief gave a sidelong glance to make sure no one was watching before entering the room.
For the record, British people have been doing this sort of thing naturally and without the aid of technology for centuries – that is, issuing a sidelong response during an awkward encounter, a protocol that escalates, in times of outright conflict, to the tangential screw-you.
Graham Greene, infamously, reviewing Wee Willie Winkie in the London weekly Night and Day, wrote: "Infancy with her is a disguise, her appeal is more secret and more adult … her neat and well-developed rump twisted in the tap dance: her eyes had a sidelong searching coquetry … watch the way she measures a man with agile studio eyes, with dimpled depravity.
By contrast, following on from his 2012 book on British independent labels, How Soon Is Now, Richard King's Original Rockers (Faber, 2 April) takes a sidelong glance at the ecosystem of the independent record shop "combining memoir and elegiac music writing".
She seems ill-at-ease, always looking sidelong at me and asking me if I'm OK.
Hay, who wonderfully described Napoleon III as moving "with a queer, sidelong gate, like a gouty crab", would ultimately become an important figure in his own right, a grand old man of the Republican Party.
Walking or crawling is the usual mode of locomotion, and the familiar sidelong gait in the common shore crab is characteristic of most members of the group.
And, with a sidelong smile – like that of a prince, a vagabond, or a demon – he touched the brim of his hat.
"Slim and elegant in those days, [Cook] was also quite vain, sensing instinctively as soon as he came into a room where the mirror was and casting pensive sidelong glances at it, while stroking his chin, as if checking on his own beauty," he recalls.
The insinuating score by Thomas Newman links together the sidelong character study of the early stages and the switchback of the latter.
What interrupts the sorrow is a humorous touch of self-awareness, never openly expressed, but perceptible in a sidelong look or a lowering of her voice.
It was all too discreet and sidelong and constipated and bloody British to be any good.
