In addition to the contract, get a spin-drier (5)
I believe the answer is:
rider
'in addition to the contract' is the definition.
I can't judge whether this definition defines the answer.
'a spin-drier' is the wordplay.
'a spin' is an anagram indicator.
'drier' anagrammed gives 'RIDER'.
'get' is the link.
Can you help me to learn more?
(Other definitions for rider that I've seen before include "knight" , "recommendation made in court" , "One in the saddle" , "one making journey" , "qualification" .)