Green’s Dictionary of Slang

1. (US, mainly prison) to cast a sidelong glance at someone.

1912		D. Lowrie My Life in Prison 189: This stiff is trying to stir up trouble all the time, he keeps dog-eyeing me.
1944		O. Ferguson ‘Vocabulary for Lakes, [etc.]’ AS XIX:2 106: And here is this big Korean dog-eyeing me all the time.
1949		Monteleone Criminal Sl. (rev. edn) 71: dog eye To scan minutely.
1953		T. Runyon In For Life 76: I [...] began to dog-eye the innocent-looking old gentlemen.
1990		S. Morgan Homeboy 122: Joe mumbled, dogeyeing his successor beneath the showerhead.

2. (US prison) to inspect, to scrutinize.

1929		D. Hammett Dain Curse 274: ‘The spick’s got herself a chive,’ he said pleasantly. [. . . .] ‘Well, keep an eye on her [...] seeing that you’re the lad she dog-eyes most, and it’s most likely you that’ll get whittled on’.
1931		Irwin Amer. Tramp and Und. Sl. 64: Dog Eye. – To inspect or scrutinize.
1962		Ragen & Finston World’s Toughest Prison 797: dog eye – To inspect or scrutinize.