Follow support for jam (8)
I believe the answer is:
tailback
'jam' is the definition.
The definition and answer can be both acts as well as being singular nouns.
Maybe there's an association between them I don't understand?
'follow support' is the wordplay.
'follow' becomes 'tail' (both can mean to chase or pursue).
'support' becomes 'back' (to back is to support or endorse).
'tail'+'back'='TAILBACK'
'for' acts as a link.
Can you help me to learn more?
(Other definitions for tailback that I've seen before include "Queue of cars" , "delayed traffic" , "Traffic hold-up" , "Sort of jam" , "Long queue of traffic" .)