Look-out duty, usually in cover of nefarious deeds.

Too much high frequency. Trebley. Harmonics are too strong relative to the fundamentals. When you view the waveform on an oscilloscope, it even looks edgy or jagged, due to excessive high frequencies. Distorted, having unwanted harmonics that add an edge or raspiness to the sound.

being in a tense state

A term used to describe a story or writing style that is unusually unsettling, exciting, or dark. Everyone claims to want edgy material, but then they end up making generic comedies.

Having some of the forms, such as drapery or the like, too sharply defined.

Easily irritated; sharp; as, an edgy temper.