Terribly wet journalist gets material (5)
I believe the answer is:
Here is my best explanation:
'material' is the definition.
(tweed is a kind of material)
'terribly wet journalist' is the subsidiary indication.
'terribly' indicates an anagram.
'journalist' becomes 'ed' (**).
'wet' anagrammed gives 'twe'.
'gets' is the link.
(Other definitions for tweed that I've seen before include "Woollen material", "Scottish and English river", "Harris cloth", "Thick woollen cloth - northern river", "Material; river", "Boundary river", "See 7", "Scottish/English river", "River; rough cloth" and "Woollen cloth - Scotland/England border river".)