Public meeting wanting tramp beheaded (5)
I believe the answer is:
forum
'public meeting' is the definition.
(I've seen this in another clue)
'wanting tramp beheaded' is the wordplay.
'wanting' becomes 'for' (I've seen this in other clues).
'tramp' becomes 'bum' (both can mean a homeless person).
'beheaded' means to remove the first letter (the head of the word is removed).
'bum' with its first letter taken away is 'um'.
'for'+'um'='FORUM'
(Other definitions for forum that I've seen before include "Meeting of people for discussion" , "Place for open discussion" , "Court - conference" , "Tribunal" , "A place for discussing" .)