斬釘截鐵

To chop or cut; to sever a connection; to behead as capital punishment.

A metal spike used to fasten things; to fasten with a spike; to stare intently; to supervise or urge someone.

to cut off; to intercept; to stop; a section or chunk; classifier for sections or segments.

Iron, the metal (Fe); weapons; surname; hard; strong; determined; unshakeable.