This is such an important word to English GCSE that it deserves its own pop-up box!
When you write succinctly about a subject, you avoid 'waffle' - your writing is economical. This means that EVERY word counts - no flab! - each word helps your reader understand your point of view and why you hold it. Succinct writing creates crisp sounding sentences - of varied length but often quite short; and always to the point.
The sentences of succinct, economical writing build up into a structure of clear and interesting paragraphs of perhaps five or six sentences each. Each of its paragraphs will begin with a sentence that clearly introduces the main point of the paragraph (called the 'topic sentence'). The remaining sentences do no more than explain this point (in an essay, they often use a quotation followed with a discussion on its literary qualities).