Incurious having no debts to fall into (5)
I believe the answer is:
incur
'fall into' is the definition.
(I've seen this before)
'incurious having no debts' is the wordplay.
'having no' suggests deleting specific letters.
'debts' becomes 'IOUs' (promises to pay debts).
'incurious' with 'ious' removed is 'INCUR'.
'to' is the link.
(Other definitions for incur that I've seen before include "Enter into" , "Sustain" , "Bring on as a consequence" , "Attract" , "Take on (obligation)" .)