Some of loan is deferred when starting firm (5)
I believe the answer is:
solid
'firm' is the definition.
(I know that firm can be written as solid)
'some of loan is deferred when starting' is the wordplay.
'when starting' says to take the initial letters.
The initial letters of 'some of loan is deferred' is 'SOLID'.
(Other definitions for solid that I've seen before include "Concrete or reilable" , "Weighty" , "Firm and stable" , "Hard and compact" , "Shape with three dimensions" .)