Left-hand muting is a performance technique for stringed instruments, where string vibration is damped by the fingering hand.
Lifting the left hand stops or suppresses the resonating string.
[1] Strumming barre chords or other chords in which there are no open strings, left-hand muting may punctuate the rhythm, so that instead of the continuous ringing sound of the strumming, short silences are introduced.
Left-hand muting is used to produce chops (chords that are released the instant after picking).
If muted strings are played with a single stroke, hitting a non-muted strings loud and clear, the result is a rake, where muted notes act as a percussive lead to the main note.