Tramp with a large rear end from Falkirk (4)
I believe the answer is:
walk
'tramp' is the definition.
(thesaurus)
'with a large rear end from falkirk' is the wordplay.
'with' indicates putting letters inside.
'a large' becomes 'L' (eg in clothes sizes).
'rear' says the letters should be written in reverse (I've seen 'rearing' mean this (as in a horse rearing up)).
'end from falkirk' becomes 'kaw' (I can't justify this - if you can you should believe this answer much more).
'kaw' backwards is 'wak'.
'l' inserted into 'wak' is 'WALK'.
Can you help me to learn more?
(Other definitions for walk that I've seen before include "Proceed on foot" , "Stretch one's legs" , "Amble" , "Go on foot" , "Perambulate" .)