Material collected by the old man, socialist geared up (8)
I believe the answer is:
prepared
'geared up' is the definition.
('prepare' can be a synonym of 'gear up')
'material collected by the old man socialist' is the wordplay.
'material' becomes 'rep' (rep is a kind of material**).
'collected by' means one lot of letters goes inside another.
'the old man' becomes 'pa' ('pa' can be a synonym of 'old man').
'socialist' becomes 'red' (red is a kind of socialist).
'rep' put inside 'pa' is 'prepa'.
'prepa'+'red'='PREPARED'
(Other definitions for prepared that I've seen before include "Waiting" , "All set" , "edited" , "Made or got ready" , "Ready for action" .)