1. a brief summary, encapsulate
sum up the importance of something/somebody
To 'sum something up' means to give a short or brief summary. If you 'sum up' a speech, report or lesson you give the main information again or describe the main points as briefly as possible. In law, during a court trial, a judge may 'sum up' the main information in a case that the jury should consider. This is a phrasal verb use both in social and professional contexts.