Smashed strip of wood with broken reed (10)
I believe the answer is:
splintered
'smashed' is the definition.
(synonyms)
'strip of wood with broken reed' is the wordplay.
'strip of wood' becomes 'splint' (I've seen this before).
'with' says to put letters next to each other.
'broken' indicates an anagram.
'reed' with letters rearranged gives 'ered'.
'splint'+'ered'='SPLINTERED'
(Other definitions for splintered that I've seen before include "Fragmented" , "carpenter's fingers may be?" , "Shattered" .)