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These are archaic terms for common law offences that are now defined by s.5 of the Criminal law act 1967. 'Compounding' is accepting reward for withholding prosection. 'Misprision' is failing to report an offence to the police, again for reward. s.5 only applies in respect of arrestable offences, and specifically excluded all other common law offences of compounding and misprision (except of Treason). It is therefore not an offence to accept reward to fail to disclose a non-arrestable offence. A further, specific exemption from s.5 exists where the compounding or misprision is by the victim of the offence, and the reward offered is by way of compensation for the offence itself.

Both offences are indictable, and liable to two years' imprisonment.