Firm holding one new cushy job (8)
I believe the answer is:
sinecure
'cushy job' is the definition.
(I've seen this before)
'firm holding one new' is the wordplay.
'firm' becomes 'secure' (similar in meaning).
'holding' is an insertion indicator.
'one' becomes 'i' (Roman numeral).
'new' becomes 'n' (common abbreviation eg NT for New Testament).
'i'+'n'='in'
'secure' going around 'in' is 'SINECURE'.
(Other definitions for sinecure that I've seen before include "Paid job with minimal work - insecure (anag)" , "Undemanding job" , "Insecure in easy job" , "Soft job, may be insecure" , "Job for easy money" .)