Green’s Dictionary of Slang

a look, a glance.

1993		I. Welsh Trainspotting 4: Ah’d git hit fir fuckin back charges [...] oan a video ah hudnae even goat a deek at.
2001		OnLine Dict. of Playground Sl. 🌐 deeks n. To see something: eg ‘Give us a deeks at that eh!’.
2015		I. Welsh Decent Ride 30: Ah decide tae [...] git a wee deek at they relived faces.