slit-eyed 
adjective
Having long, narrow eyes, or eyes narrowed by squinting: he gave me a slit-eyed look she stared, slit-eyed, down the length of the gun...
- For me ‘the strong, silent type’ conjures up images of slit-eyed Clint Eastwood, mumbling a few well chosen syllables before dispatching some low-life to oblivion with his enormous gun.
- The feldspar statue keeps intent, slit-eyed watch over a tomb.
- Lempicka, with helmet and gauntlets, but over-lipsticked, has her eye on the road in slit-eyed girlish triumph.