A woody tropical grass (6)
I believe the answer is:
bamboo
'a woody tropical grass' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for bamboo that I've seen before include "Tropical cane with hollow centres, used for furniture" , "Fast-growing woody grass" , "Tall wood plant" , "Tall woody plant" , "Panda's dinner?" .)