Toss stone (4)
I believe the answer is:
rock
This clue is a double definition.
'toss' is the first definition.
(thesaurus)
'stone' is the second definition.
(I know that stone can be written as rock)
(Other definitions for rock that I've seen before include "possible danger at sea" , "Edinburgh - -" , "Shake; boulder" , "Sway - very big stone" , "Large stone - type of music" .)