Easy to work with small dissertation (5)
I believe the answer is:
essay
'dissertation' is the definition.
(I've seen this in another clue)
'easy to work with small' is the wordplay.
'to work with' indicates anagramming the letters (letters worked into a new order).
'small' becomes 's' (abbreviation - e.g. clothes size).
'easy' anagrammed with 's' gives 'ESSAY'.
(Other definitions for essay that I've seen before include "Composition, paper, article" , "Try; a piece of writing" , "Short literary piece: attempt" , "Make an effort or attempt" , "Short treatise" .)