Wild goer's boxing uniform, almost see-through (8)
I believe the answer is:
gossamer
'see-through' is the definition.
('gossamer' can be a synonym of 'see-through')
'wild goer's boxing uniform almost' is the wordplay.
'wild' indicates an anagram.
'boxing' means one lot of letters goes inside another ('box' can mean contain, as in to put in a box).
'uniform almost' becomes 'sam' (I am not sure about this - if you are sure you should believe this answer much more).
'goers' is an anagram of 'goser'.
'goser' enclosing 'sam' is 'GOSSAMER'.
Can you help me to learn more?
(Other definitions for gossamer that I've seen before include "Very thin material" , "Very finest textured silk" , "Filmy threads seen on hedges" , "Filmy floating cobweb" , "Some rags (anag.)" .)