razor

razor /ˈreɪzɚ/ noun
plural razors
razor
/ˈreɪzɚ/
noun
plural razors
Britannica Dictionary definition of RAZOR
[count]
: a tool or device with a sharp edge that is used to shave or cut hair from the face, body, or head — see picture at grooming

razor's edge

or razor edge
— used in various phrases to refer to a dangerous position or a position in which two different things are carefully balanced