Thin spears broken (6)
I believe the answer is:
sparse
'thin' is the definition.
(I know that thin can be written as sparse)
'spears broken' is the wordplay.
'broken' indicates anagramming the letters.
'spears' with letters rearranged gives 'SPARSE'.
(Other definitions for sparse that I've seen before include "Thinly spread" , "Far from lavish" , "Scarce like thinning hair" , "Thinly dispersed" , "Rare" .)