Acrobats in glasses (8)
I believe the answer is:
tumblers
This clue is a double definition.
'acrobats' is the first definition.
('tumbler' can be a synonym of 'acrobat')
'glasses?' is the second definition.
(tumbler is a kind of glass)
'in' is the link.
(Other definitions for tumblers that I've seen before include "circus acts?" , "gymnasts" , "Glasses with flat bottom and no handle or stem" , "Pigeons" , "Acrobats and drinking vessels" .)