eagle-eyed, adj. — Green’s Dictionary of Slang

eagle-eyed adj.

[the visual acuity of the bird; note SE eagle-eyed, keen-sighted]

scrutinizing, paying close attention, watching.

1900

‘Doss Chiderdoss’ ‘The Victimless Villain’ Sporting Times 3 Mar. 1/4: As his eagle-eyed optic (the man was one-eyed) / Glared forbiddingly round o’er the whole countryside.