Prohibition covering some tropical tree (6)
I believe the answer is:
banyan
'tropical tree' is the definition.
(I've seen this in another clue)
'prohibition covering some' is the wordplay.
'prohibition' becomes 'ban' (synonyms).
'covering' is an insertion indicator.
'some' becomes 'any' (similar in meaning).
'ban' enclosing 'any' is 'BANYAN'.
(Other definitions for banyan that I've seen before include "Fig-tree found in th bay, Nan." , "one that does give a fig" , "plant" , "Multi-trunked Indian tree" , "Fig tree with aerial roots" .)