Composition engaging swots, primarily, for example (5)
I believe the answer is:
essay
'composition' is the definition.
(I've seen this in another clue)
'engaging swots primarily for example' is the wordplay.
'primarily' indicates taking the first letters.
'for example' becomes 'say' ('say' can be used to introduce an example).
The first letters of 'engaging swots' is 'es'.
'es'+'say'='ESSAY'
(Other definitions for essay that I've seen before include "Short literary piece: attempt" , "Attempt, try" , "Have a shot at a written piece" , "Try; a piece of writing" , "What may be written in exam" .)