Get smaller and lighter (5)
I believe the answer is:
taper
I believe this clue is a double definition.
'get smaller' is the first definition.
(to taper is to narrow or become smaller)
'lighter' is the second definition.
(I've seen this before)
'and' is the link.
(Other definitions for taper that I've seen before include "Waxed spill" , "Thin wick" , "recording artist" , "He records" , "Give a point" .)