Final answer:
An indictable offence is a serious criminal offence, typically requiring a grand jury indictment before prosecution, as specified by the Fifth Amendment.
Step-by-step explanation:
An indictable offence under the criminal code does indeed refer to a serious criminal offence. This aligns with the principles found in the Fifth Amendment, which specifies that serious crimes, including capital or otherwise infamous crimes, are prosecuted only after an indictment by a grand jury. There are some exceptions to this, for example, in cases arising within the military or in states that use a preliminary hearing instead of a grand jury. Nevertheless, the core idea remains that an indictable offence is severe in nature and requires a formal charging process before prosecution can proceed.