Premeditation is the act of thinking something through and planning it before you do it. In everyday life we plan all the time, but this noun is at home in law. Prosecutors try to show premeditation; defence lawyers try to show there was none — that a person snapped, and did not sit with the idea first. You will often meet the set phrase with premeditation, especially with murder. It feels formal and heavy. Though actually, outside court it is rare: a friend would just say “they planned it.” The legal point is the gap in time: not the cleverness of the plan, but that the mind had already said yes before the hands moved.