What one might use to lash out? (7)
![Ross](/clue/static/ross-mug.min.png)
I believe the answer is:
mascara
(Other definitions for mascara that I've seen before include "Cosmetic for the eyes" , "facial cosmetic" , "black application" , "Makeup used to darken and thicken the eye lashes" , "Cosmetic for darkening the eyelashes" .)