Wander but not at first in leisurely walk (5)
I believe the answer is:
amble
'leisurely walk' is the definition.
(casual or relaxed walk)
'wander but not at first' is the wordplay.
'wander' becomes 'ramble' (synonyms).
'but not at first' means to remove the first letter.
'ramble' with its first letter removed is 'AMBLE'.
'in' is the link.
(Other definitions for amble that I've seen before include "Move at an easy pace" , "Take leisurely stroll" , "Walk along slowly" , "Walk in a leisurely way" , "Blame (anag.)" .)