Had a tramp cooked up drug taken by old rocker? (7)
I believe the answer is:
trudged
'had a tramp' is the definition.
(to trudge is to tramp around)
'cooked up drug taken by old rocker?' is the wordplay.
'cooked up' indicates an anagram.
'taken by' is an insertion indicator.
'old rocker?' becomes 'ted'.
'drug' anagrammed gives 'rudg'.
'rudg' inserted within 'ted' is 'TRUDGED'.
(Other definitions for trudged that I've seen before include "plodded wearily" , "Traipsed" .)