ra·zor edge (also ra·zor's edge) • n. a sharp edge of a knife, ax, or similar implement. ∎ fig. a state of sharp incisiveness: he had honed his mind to a razor edge. ∎ (the razor edge) fig. the most advanced stage in the development of something; the cutting edge: in 1960 jet planes were the razor edge of chic.PHRASES: on the razor's edge in a precarious or dangerous position: it is commonplace to believe that Finns live on the razor's edge, at the mercy of their powerful neighbor.DERIVATIVES: ra·zor-edged adj.