Tramp pocketing pound, in case (4)
I believe the answer is:
plod
'tramp' is the definition.
(both can mean to walk around heavily)
'pocketing pound in case' is the wordplay.
'pocketing' indicates putting letters inside (pocket can mean to steal or take possession of).
'pound' becomes 'L' (abbreviation e.g. Lsd - pounds, shillings, pence).
'in case' becomes 'pod' (pod is a kind of case. I am not sure about the 'in' bit.).
'l' placed within 'pod' is 'PLOD'.
Can you help me to learn more?
(Other definitions for plod that I've seen before include "Policeman - walk slowly" , "coppers?" , "Walk like ploughman or policeman?" , "Stomp" , "Work (or walk) laboriously" .)