Gets narrower (6)
I believe the answer is:
tapers
'gets narrower' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for tapers that I've seen before include "Makes or becomes gradually narrower" , "Narrows towards the end, like a candle" , "Prates about slender candles" , "Long thin candles" , "Narrows toward a point" .)