Something that floats, leaves (7)
I believe the answer is:
iceberg
I believe this clue is a double definition.
'something that floats' is the first definition.
(icebergs float)
'leaves' is the second definition.
(leafy lettuce)
(Other definitions for iceberg that I've seen before include "Mass calved from a glacier" , "Titanic sinker - lettuce" , "Floating piece from glacier" , "Maritime danger, mostly underwater" , "danger at sea" .)