辜 death penalty

辜 is a phono-semantic character. In the seal script, 辜  =  (古)+ (辛).   

辛, a square knife used to tattoo a criminal’s face for identification, is the semantic component.

古 means past or ancient and serves as the phonetic component, indicating that the crime is convicted in accordance with past cases.

The original meaning of 辜 is death penalty.

Its extended meanings are:

A. crime, guilt, for example, 死有余辜 even death would be too good for sb., 无辜 be innocent

B. let down, fail to live up to 辜负, 你辜负了他的期望。You‘ve let him down.