Take in duke initially (5)
I believe the answer is:
first
'initially' is the definition.
(thesaurus)
'take in duke' is the wordplay.
'take' becomes 'r' (recipe is latin for take - r is abbreviation).
'in' means one lot of letters goes inside another.
'duke' becomes 'fist' (put up your dukes).
'r' put into 'fist' is 'FIRST'.
(Other definitions for first that I've seen before include "Pre-eminent" , "Preceding all others" , "Position for gold" , "at the outset" , "in dominant position" .)