If looks could kill…
Definition 1 of 1
Pro Tip 1/3Anger Intensity
This phrase exaggerates the power of someone's angry look to cause harm. 
At the meeting, Lisa's glare was so severe — if looks could kill, we'd all be in trouble.
Pro Tip 2/3Not Literal
Remember, the phrase is metaphorical and humorous, not a literal threat. 
Mom found out I lied - if looks could kill, I'd have vanished on the spot!
Pro Tip 3/3High Tension
Use when describing situations where there's a lot of unspoken anger or disapproval. 
If looks could kill, the silence between the two rivals could have been deadly.