Crossing stars never move (10)
I believe the answer is:
transverse
'crossing' is the definition.
(synonyms)
'stars never move' is the wordplay.
'move' indicates anagramming the letters.
'stars'+'never'='starsnever'
'starsnever' with letters rearranged gives 'TRANSVERSE'.
(Other definitions for transverse that I've seen before include "Extending across (the long axis)" , "Cross" , "Crossing" , "Crosswise" , "Extending across something" .)