Pay attention and steal a fifty (4,4)
I believe the answer is:
take note
'pay attention' is the definition.
(I've seen this in another clue)
'steal a fifty' is the wordplay.
'steal' becomes 'take' (to steal is to take without permission).
'a fifty' becomes 'note' (I can't explain this - if you can you should give a lot more credence to this answer).
'take'+'note'='TAKE NOTE'
'and' is the link.
Can you help me to learn more?
(Other definitions for take note that I've seen before include "Observe and absorb - jot it down" , "what the stenographer does" , "mark?" , "Pay attention" , "Observe closely" .)