Material comes adrift around big person (8)
I believe the answer is:
strapper
'big person' is the definition.
(strapper can mean a big person, someone strapping)
'material comes adrift around' is the wordplay.
'material' becomes 'rep' (rep is a kind of material**).
'comes adrift' becomes 'parts'.
'around' says the letters should be written in reverse.
'rep'+'parts'='repparts'
'repparts' backwards is 'STRAPPER'.
(Other definitions for strapper that I've seen before include "Big fellow" , "lie" .)