Writing, say, incorporated into loan (6)
I believe the answer is:
legend
'writing' is the definition.
(legend is a kind of writing)
'say incorporated into loan' is the wordplay.
'say' becomes 'eg'.
'incorporated into' indicates putting letters inside.
'loan' becomes 'lend' ('lend' can be a synonym of 'loan').
'eg' going inside 'lend' is 'LEGEND'.
(Other definitions for legend that I've seen before include "Story of mythical beings or events" , "hero" , "Saga" , "Myth or fable" , "Story from long ago" .)