Tramp raised pack horse (5)
I believe the answer is:
march
'tramp' is the definition.
(thesaurus)
'raised pack horse' is the wordplay.
'raised' shows that the letters should be reversed in order.
'pack' becomes 'cram' ('cram' can be a synonym of 'pack'**).
'horse' becomes 'h' ('H' can be a synonym of 'horse').
'cram' reversed gives 'marc'.
'marc'+'h'='MARCH'
(Other definitions for march that I've seen before include "Walk smartly" , "Colonel Bogey, for example" , "Protest; month" , "Stride; month" , "Walk in a resolute manner" .)