Body of Church unaltered accommodating Saint (7)
I believe the answer is:
chassis
'body' is the definition.
(chassis is a kind of body)
'church unaltered accommodating saint' is the wordplay.
'church' becomes 'ch' (common abbreviation).
'unaltered' becomes 'asis' (I've seen this in other clues).
'accommodating' indicates putting letters inside.
'saint' becomes 's'.
'asis' going around 's' is 'assis'.
'ch'+'assis'='CHASSIS'
'of' is the link.
(Other definitions for chassis that I've seen before include "Bodywork" , "Undercarriage" , "Car's body" , "Car's structural framework" , "an estate may be built on it" .)