cut to the quick

:  to penetrate with or as if with an edged instrument

:  to hurt the feelings of

:  to strike sharply with a cutting effect

:  a product of cutting: such as

:  an opening made with an edged instrument

:  a wound made by something sharp :  gash

:  marked by a well-developed and highly defined musculature

:  not dead :  living, alive

:  acting or capable of acting with speed: such as

:  fast in understanding, thinking, or learning :  mentally agile

:  living beings

:  a painfully sensitive spot or area of flesh (such as that underlying a fingernail or toenail)

:  the inmost sensibilities

:  in a quick manner