Joyful expression encapsulating the author's particular way with words (6)
I believe the answer is:
simile
'particular way with words' is the definition.
I can't judge whether this definition defines the answer.
'joyful expression encapsulating the author's' is the wordplay.
'joyful expression' becomes 'sile' (I can't explain this - if you can you should believe this answer much more).
'encapsulating' means one lot of letters goes inside another (I've seen this in other clues).
'the author's' becomes 'Im' ('I am' referring to the author of the crossword).
'sile' going around 'im' is 'SIMILE'.
Can you help me to learn more?
(Other definitions for simile that I've seen before include "as silly as a loon, say" , "Figure of speech making straightforward comparison" , "Most common figure of speech, one of comparison" , "as daft as a brush, say" , "Figure of speech in which one thing is likened to another" .)