Invigorating chapter by Morrison (5)
I believe the answer is:
tonic
'invigorating' is the definition.
(similar in meaning)
'chapter by morrison' is the wordplay.
'chapter' becomes 'c' (abbreviation).
'by' says to put letters next to each other.
'morrison' becomes 'Toni' (Toni Morrison).
'c' after 'toni' is 'TONIC'.
(Other definitions for tonic that I've seen before include "something providing a boost" , "Keynote of a scale" , "something medicinal" , "Restorative that invigorates" , "Fillip" .)