A: actus reus: An act of crime must have actus reus (the act) and mens rea (the intention) to form an act of crime. If one of these is missing, then it will not amount to a crime.
M: mens rea: mens rea (the intention) has to be present with actus reus (an act) to constitute a criminal act. In absence of mens rea, an act alone can not be a criminal offence. For example, if A breaks into a shop at night to steal things then the act (actus reus) is breaking in, and the intention (mens rea) is to steal things.
Now consider this; A sees a man (probably a security guard) inside a shop who seems to having a stroke. The shop is locked from inside so A kicks the door in and enters the shop. Phones the ambulance and waits with the guard. Now in this situation he has still broken in but the intention was not to steal. So there is no mens rea and therefore breaking in would not be a criminal offence.
N: novus actus interveniens = a new act that takes place between the previous two events and thus breaks the chain of events. Example, A shots B in the leg – B is taken into a hospital where the doctor negligently injects him with a drug that B is severely allergic to and as a consequence he dies. In this scenario the doctor’ act would be the novus actus interveniens
O: obiter dictum is usually used in plural form as obiter dicta and it is a remark by a judge in the course of a judgement. The remark can be an opinion, expression or simply saying “by the way”. Obiter dictum is not essential to the decision and can be oral or in writing and does not bind legally.
P: prima facie ˌthe apparent cause or the impression that appears to be the primary reason for a cause. It is basically pinpointing to a person or thing that appears to have done somethng as it appears so far by the evidence in hand – unless there is another evidence that suggest otherwise.
volenti non fit injuria: is a defence in tort law and what it means is that if a person willingly takes a risk, knowing that there is a risk, then he cannot sue for injuries caused by that risk.